Also, just thought I'd mention I'm really happy with the Quads after a week of listening to them for several hours a day. My Senns are sulking!
Despite flirting with the Little Dot MkVI, I've pretty much decided to stay with a single-ended setup rather than go to the hassle (and expense) of finding a balanced source I like as much as the Duet. So really the main question left is what's out there in the <$1,000 category that would be a solid step up from my current LD MkIVse as a combo headphone amp and speaker preamp?
I'm a bit stumped for ideas, unless someone wants to sell me Zana Deux for a grand?