Well, let's see... I've got 180 large to make a movie with. I can rent a RED or an ARRI. Or I can use the three GH1's I can get for free and do a three camera shoot. Or if I really want the "film look" I can do super 16. My LD is an artist. He can make VHS look good. Do people who actually pay to see movies really care about a rolling shutter?
What to do...?
There is no reason it has to be just one or the other. The GH1 could be used for scenes that play to its strengths and short term rental of a better camera could supplement for shots that involve things like fast action or camera movements that the DSLR's don't do so well.
It doesn't matter how sensitive a camera is, you still have to light a movie if you want consistent look and quality. So I don't think ultra low light sensitivity is all that critical.