I've used Cakephp and Rails,
Both of which I found frustrating but I can see the attractions.
I've used 960 grid system as well for layout if thats what you meant.
Yes, around Thesis.
I use Thesis. Yes, a lot of people don't take the time to customize it. But it's so simple to edit and add a lot of stuff too. I mean, I barely recognize Thesis on one of my own blogs.
I have tried other frameworks to build off of too. 960 Grid system is pretty nice I have to admit!