What Is Best Speaker for $8000 - $10,000, used ?

I'm looking to upgrade my speakers to get more resolution, definition, dynamics, soundstage, etc. My budget allows up to $10,000 or so, on the used market. The speakers should be able to accomodate near wall placement, since I can't pull them out 3' from the wall. So, preference will be given to non-rear ported designs. My system is solid state gear and running 400+ watts per channel. The room is 20x22 with a very high ceiling and, presently I am using Piega P10's. Thanks.