I've been using a Peavey TNT115S that I got for cheap with my bass and occasionally with a moog-cordovox white elephant organ.
It sounds really good, especially with the built in chorus feature on the amp. My worry is that the bass keys might damage the speaker, the sustained lows and all. Any clue?
I have a good friend who's a wicked keyboard/organ/syth player who does a funk band that's just Keys/Drums/Vocals. He's been using bass cabs for parts of his rig for years.
He does tend to kill bass gear fairly easily though. I would suggest that he overheats the speakers by sending lots of lows for extended periods of time and that ends up killing his coils.