I haven't tried it, but those are such good sounding cabinets, I would have to think it would sound pretty good. Only downside is you'd only be running at 250w. (@ 8 ohm). Given the weight of the OBC115, I think it's easier with 2 x OBC112's. They are nice and light and you can carry 2 at a time and you can set the head army 4 ohm for the full 500w.
If you're shopping for a single cab to use with your TB500, a good option would be an Ampeg SVT212AV. It's a 2x12 cab that is rated 600w and is a 4 ohm cabinet.
If you're shopping for a single cab to use with your TB500, a good option would be an Ampeg SVT212AV. It's a 2x12 cab that is rated 600w and is a 4 ohm cabinet.