I second Steve's suggestion of dual EP500's. It will even out the bass through out the room better and allow for a few more SPL.
I also second JohnK's thought of trying out the 3900 and then go from there.
As wid mentioned the 3808 from Denon is proven performer(I have one with M80s) and you might be able to get one quite cheap, as the 3809's are on their way. 6ave.com was selling the 3808 for ~$1100 IF you called them and asked for the special pricing. I have heard rumors of the 3808 for as low as $800 from various sources.
