You can always add an Eminent Technology TRW-17 True Subwoofer to your speakers (and "non-true" subs ;-) to reach $50k. If you don't yet know that Bruce Thigpen is a genius (or at least a very clever fella), check out the TRW-17. TRW stands for Thigpen Rotary Woofer, and it was designed to reproduce 20Hz and below, flat to 1Hz! Not cheap, but hey, you got $50k to play with, right?
If you're not in a hurry, you can always wait for the (possibly) upcoming model from Magnepan: the "30.7 for Condos". Midrange magnetic-planar drivers, a ribbon tweeter, and OB/dipole subs. If you can't wait, get the 30.7 and multiple GR Research/Rythmik OB/Dipole Subs. Oh, and the ET TRW-17. ;-)