I think I know the guitars you're talking about but I haven't played one myself. I do have an old Dan Armstrong which is plexiglass and it plays great and has nice tone, no complaints:

http://www.guitartricks.com/channel/?input=2

You might ask Instructor Joel Van Dijk, I think he's playing one in his Funk Guitar Tutorial:

http://www.guitartricks.com/lesson.php?input=12403&s_id=632