I don't think they do. Other than averting an Israeli missile attack (which would be limited anyway) and maybe getting some US aid, they have everything to lose. Whether you like them or not, they're on their way to becoming a serious world player once they get the bomb. The middle east pattern has generally been that once you get on the US aid dole (Egypt), you slide into irrelevance pretty quickly, except for hosting the occasional peace conference.

In other words, which factions or individuals in Iran would benefit from increased contact with the US.

It is quite clear that the wealthiest man in Iran, Rafsanjani, would like the financial embargos to be lifted so that he could become even richer. Naturally the merchant classes and upwardly mobile young people support that, for the most part. That's why Rafsanjani helped the campaigns of Mousavi, Rezai, and Karrubi against Ahmadinejad.

However the reality of the situation for most Iranians is that they are not rich, not trying to get rich, and they know very well that the US Army is at their western, eastern, and southern borders.

Not to mention Israel is threatening to destroy them virtually every day, and the US is barely restraining them.

So it's a complicated situation, I guess.