Mordante, the Monarchy SE-250 meets your requirements. 250 Watts into 8, 500 into 4, biased Class A to about 50 Watts. It also uses a 6922/6DJ8 or 12AT7 tube frontend, has NO negative FB whatever, and uses MOSFET output transistors. I've had its 'little' brother, the SE-160, for several weeks; it sounds VERY good.
http://s89.photobucket.com/albums/k220/jeffreybehr/Monarchy%20Audio/?action=view¤t=Dustyheatsinks_1280w.jpg
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http://s89.photobucket.com/albums/k220/jeffreybehr/Monarchy%20Audio/?action=view¤t=Dustyheatsinks_1280w.jpg
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