The Amiga x5000 hardware is the high-end and is on sale now. Unfortunately, it’s going to cost you a lot. Here in America, the board alone is about $1500USD and the full system about $2000.
For those that want real PPC hardware, and can’t find a used system on Amibay, there is a board that has been mentioned here before called the Tabor (A1222), a collaboration between A-EON (makers of x1000 and x5000) and Acube (creators of the SAM 440/460 line).
Here’s a screenshot of the point of install for OS4.1, so it proves that driver support is progressing and hopefully, this will results in general release of the board to the public.
No word yet on final price but it is expected to be in the $400USD price range for the motherboard from the last rumors I saw. This would be in line with the Acube SAM boards (which are long out of production).
Mambo's Amiga Blog 