It has been a while since you have posted this question
and sure you have moved on but I still wanted to post this in this forum having chosen a Loewe TV
and successfully integrated it with the rest of my B&O set up.
The reson that this maybe of interest to a Avant user is that at some stage, like I have done so, you will forced to move into a flat panel. If that is a B&O, that is fine, but in case you do consider other options this could be useful for you.
Odd enough, with BeoLab6000s at front and 4000s at the back, I was also struggling about the sound quality. Now with the new set up I am using still the same speakers but with the addition of a (Loewe) subwoofer and also possibly a better decoder on the Loewe TV than Avant, the sound has changed dramatically. I would suggest you keep your b&o speakers, they are good.
As for Avant, it is still with us. It is now on its own, without any surrond speakers and is still working great.
Rather long story, so attach a link rather than the text itself. Hope you may find it useful.
http://dl.dropbox.com/u/36715224/Loewe%20Individual%20TV%20with%20B%26O%20Speakers.pdf
Regards,