I am currently using two Barbetta 31c's. They are quite small (~32 pounds), and sound great. Excellent bass for such small cabinets. These are self-powered amp/speakers with line and mic inputs. I sometimes use a tiny Mackie or Behringer mixer if I want to mix a mic into this setup. For really small gigs, I just bring one of the Barbetta's.

Search around the Web; there are some favorible reviews of these in places such as Keyboard Magazine.

Jim