According to the Hanafi madhab, can you end the prayer before the Imam (ie before the imam does the tasleem)? I read this weird claim today and would like to verify it.
For the hanafi madhhab the tasleem is not considered a rukn (fard) but wajib (which might have the level of sunnah muakkadah or a bit more in other madhhabs). Some of their evidences is
Alqamah said that Abdullah ibn Mas'ud caught hold of his hand saying that the Messenger of Allah (ﷺ) caught hold of his (Ibn Mas'ud's) hand and taught him the tashahhud during prayer.
He then narrated the (well known ) tradition (of tashahhud). This version adds: When you say this or finish this, then you have completed your prayer. If you want to stand up, then stand, and if you want to remain sitting, then remain sitting. (Sunan abi Dawod)
This hadith shows that one can finish his prayer without tasleem, as there's no mentioning of tasleem and the hadith seems to say you can stand up right away. Another evidence is the hadith saying:
Allah's Messenger (S) said: "When he commits Hadath - meaning a man - and he is sitting in the end of his Salat before saying the Taslim, then his Salat is acceptable." (Jami' at-Tirmidhi)
As far as I know the hanafi madhhab allows to perform the tasleem at the same time with the Imam according abu Hanifa himself, while abu Yusuf and Mohammad ibn al-Hassan follow the opinion of the majority, here a quote from bada'i as-sana'i بدائع الصنائع في ترتيب الشرائع of al-Kassani:
ومنها أن يسلم مقارنا لتسليم الإمام إن كان مقتديا في رواية عن أبي حنيفة كما في التكبير ، وفي رواية يسلم بعد تسليمه وهو قول أبي يوسف ومحمد كما قالا في التكبير
( MY OWN TRANSLATION TAKE IT CAREFULLY)
And among these (the sunan of tasleem) is to say the tasleem at the same time with the imam in one narration from abu Hanifa -as is the case for takbeer-, and in an other -narration- to say tasleem after the imam and this is the opinion of abu Yusuf and Mohammad -as they've said about takbeer-.
(but one could leave the prayer before the tasleem as long as one has been sitting for the necessary time to perform tashahhud and could "repair the prayer" by perfroming sujud shaw if it was not intended else one would be sinning) in congregation as the act of tasleem is not rukn (fard) in the hanafi madhhab and this is covered in my answer here with references from hanafi books: Catching Salat just before the last word of last Salam you could also read here in bada' as-sana'i the argumentaion, why they claim it is not rukn.
Note that in case of forgetfulness in all madhhabs performing tasleem before the imam doesn't invalidate the prayer (see this fatwa on islamonline).