I've only seen them in photos, not personally. There's no reason why it wouldn't work on a bass. After all, you're not trying to have a floating top like a true acoustic. The smaller volume would no doubt make it sound a little different, but you'd have to build it to find out the difference.
About this time last year, MS sent out its spring catalog with a special edition gold top Keifer Sutherland 336 on the cover. Now there's a ringing endorsement.