If you can turn this sideways in your closet, you might have found the ticket. The Audion Sterling runs 12W of SET power, and runs in ultralinear mode at a certain volume output. Thus, you get a smooth midrange and a punchy bass response. Excuse me if my terminology is not spot on, but I think you get the picture. The amp is 9" in width.
http://cls.audiogon.com/cgi-bin/cls.pl?ampstube&1108445089
http://cls.audiogon.com/cgi-bin/cls.pl?ampstube&1108445089