I don't run Hubzilla, but I have streams and Forte running on a shared server. It works, mostly.

I think the biggest annoyance is that I can't control Apache settings. "Authorization: Basic" headers are blocked on my server, and I still haven't discovered how to work around this. So WebDAV and a few other features do not work. (It's my hosting service specifically, and not shared hosting in general -- other people don't have this problem.)

Because of this, I can't recommend pair.com. I have seen good things about ScalaHosting, but I haven't tried them yet.