If we do not consider anythong other than the Quran, do we have support or command for forming islamic governments?
I only want references from Quran.
No hadith, no qiyas, no istislah, no ijma, just Quran.
The verses of Surah Maidah are particularly clear when they say "whoever does not judge by what Allah has revealed, those are the wrongdoers (or disobedient or disbelievers)."
However, there are other verses as well that prove the fact that Islamic rule should be established.
Firstly, verses that tell us to struggle until the religion is established for Allah:
Fight them until there is no [more] fitnah and [until] religion is [acknowledged to be] for Allah. But if they cease, then there is to be no aggression except against the oppressors. (2:193)
And fight them until there is no fitnah and [until] the religion, all of it, is for Allah. And if they cease - then indeed, Allah is Seeing of what they do. (8:39)
Secondly, verses that say legislation or hukm is only for Allah:
Say, "Indeed, I am on clear evidence from my Lord, and you have denied it. I do not have that for which you are impatient. Legislation is only for Allah. He relates the truth, and He is the best of deciders." (6:57)
You worship not besides Him except [mere] names you have named them, you and your fathers, for which Allah has sent down no authority. Legislation is not but for Allah. He has commanded that you worship not except Him. That is the correct religion, but most of the people do not know. (12:40)
Thirdly, countless verses give us commands that relate to laws and punishment. Obviously, everyone has agreed there is no vigilantism in Islam! These commands themselves mean there must be an Islamic government or else we won't be able to apply them:
The [unmarried] woman or [unmarried] man found guilty of sexual intercourse - lash each one of them with a hundred lashes, and do not be taken by pity for them in the religion of Allah, if you should believe in Allah and the Last Day. And let a group of the believers witness their punishment. (24:2)
And those who accuse chaste women and then do not produce four witnesses - lash them with eighty lashes and do not accept from them testimony ever after. And those are the defiantly disobedient. (24:4)
[As for] the thief, the male and the female, amputate their hands in recompense for what they committed as a deterrent [punishment] from Allah. And Allah is Exalted in Might and Wise. (5:38)
O you who have believed, prescribed for you is legal retribution for those murdered - the free for the free, the slave for the slave, and the female for the female. But whoever overlooks from his brother anything, then there should be a suitable follow-up and payment to him with good conduct. This is an alleviation from your Lord and a mercy. But whoever transgresses after that will have a painful punishment. (2:178)
Fourthly, Allah forbids following personal inclinations in the matter of justice i.e. you can only follow Allah's commands:
O you who have believed, be persistently standing firm in justice, witnesses for Allah, even if it be against yourselves or parents and relatives. Whether one is rich or poor, Allah is more worthy of both. So follow not [personal] inclination, lest you not be just. And if you distort [your testimony] or refuse [to give it], then indeed Allah is ever, with what you do, Acquainted. (4:135)
[We said], "O David, indeed We have made you a successor upon the earth, so judge between the people in truth and do not follow [your own] desire, as it will lead you astray from the way of Allah." Indeed, those who go astray from the way of Allah will have a severe punishment for having forgotten the Day of Account. (38:26)
Fifthly, Allah criticizes those who want the judgement other than His own:
Then is it the judgement of [the time of] ignorance they desire? But who is better than Allah in judgement for a people who are certain [in faith]. (5:50)
Is not Allah the most just of judges? (95:8)
Sixthly, Allah negates the Iman of people that do not make the Prophet (SAW) and by extension the religion the judge in all their matters:
But no, by your Lord, they will not [truly] believe until they make you, [O Muhammad], judge concerning that over which they dispute among themselves and then find within themselves no discomfort from what you have judged and submit in [full, willing] submission. (4:65)
Seventhly, Allah informs us that the government and those in authority should themselves be beholden to Islam:
O you who have believed, obey Allah and obey the Messenger and those in authority among you. And if you disagree over anything, refer it to Allah and the Messenger, if you should believe in Allah and the Last Day. That is the best [way] and best in result. (4:59)
And many more verses can be mentioned. There is no room for doubt that the Quran mandates establishing law according to the rules God has sent down.
These are the verses of Quran that support Islamic government or that command to judge by what Allah has revealed.
5:44
Indeed, We sent down the Torah, in which was guidance and light. The prophets who submitted [to Allah] judged by it for the Jews, as did the rabbis and scholars by that with which they were entrusted of the Scripture of Allah, and they were witnesses thereto. So do not fear the people but fear Me, and do not exchange My verses for a small price [i.e., worldly gain]. And whoever does not judge by what Allah has revealed - then it is those who are the disbelievers.
— Saheeh International
5:45
And We ordained for them therein a life for a life, an eye for an eye, a nose for a nose, an ear for an ear, a tooth for a tooth, and for wounds is legal retribution. But whoever gives [up his right as] charity, it is an expiation for him. And whoever does not judge by what Allah has revealed - then it is those who are the wrongdoers [i.e., the unjust].
— Saheeh International
5:47
And let the People of the Gospel judge by what Allah has revealed therein. And whoever does not judge by what Allah has revealed - then it is those who are the defiantly disobedient.
— Saheeh International
5:49
And judge, [O Muḥammad], between them by what Allah has revealed and do not follow their inclinations and beware of them, lest they tempt you away from some of what Allah has revealed to you. And if they turn away - then know that Allah only intends to afflict them with some of their [own] sins. And indeed, many among the people are defiantly disobedient.
— Saheeh International
Allah prescribed laws for His Prophets to judge their people with, i.e. the Shari'a is a must for a proper Muslim society:
( 5/44 ) Indeed, We sent down the Torah, in which was guidance and light. The prophets who submitted [to Allah] judged by it for the Jews, as did the rabbis and scholars by that with which they were entrusted of the Scripture of Allah, and they were witnesses thereto. So do not fear the people but fear Me, and do not exchange My verses for a small price. And whoever does not judge by what Allah has revealed - then it is those who are the disbelievers.
( 5/45 ) And We ordained for them therein a life for a life, an eye for an eye, a nose for a nose, an ear for an ear, a tooth for a tooth, and for wounds is legal retribution. But whoever gives [up his right as] charity, it is an expiation for him. And whoever does not judge by what Allah has revealed - then it is those who are the wrongdoers.
( 5/46 ) And We sent, following in their footsteps, Jesus, the son of Mary, confirming that which came before him in the Torah; and We gave him the Gospel, in which was guidance and light and confirming that which preceded it of the Torah as guidance and instruction for the righteous.
( 5/47 ) And let the People of the Gospel judge by what Allah has revealed therein. And whoever does not judge by what Allah has revealed - then it is those who are the defiantly disobedient.