Keystone Locomotive Works makes a kit for a dandy little caboose, not much larger than a 4-wheel bobber, but has two trucks, and (in my seldom humble opinion) is better looking than the bobbers.
It is definately a "craftsman" kit in the "old style" with die cast metal parts and some wood parts. But it builds up really nice, and because of all the parts is really easy to kit bash and/or customize. Its prototype was a logging caboose.
If you cannot find it elsewhere, look on page 193 of the 2002 Walthers HO catalog.
Bill