If you are thinking Pentax 645D go look at theses images on this thread over at the pentad forum:
The camera is very capable, in the right hands of course, the biggest challenge is finding lenses for it. Mostly used eBay stuff, some new "old stock"
But... if you are willing to go this route, you can save a lot of money, and even though there are very few 645D shooters here on GETDPI, I don't think anyone here can say that the body is not an excellent camera for 10K.
Nothing can touch it at that price in MF. A used P30+ back with warranty is 8-9K I believe, and then you have to get the DF body, another 5700 or so..
ps. Signing up for one of Guy and Jacks workshop is an excellent idea, They have all the "toys" and you can see for yourself if MF is something you even want to venture into at any price point
Also keep in mind I am sure Canon and Nikon have some higher MP cameras coming out soon, that maybe in the hi 30MP range, though then I think you would be forced to buy all manual focus zeiss glass that can deliver the resolution for so many pixels.