I can't understand why people keep on menitioning that they don't want to upgrade their camera bodies every three years or so, compared to the price of the back the camera costs nothing. Imagine the 1ds Mk3 sensor in a 1DS Mk1 Body, the least thing I want. Current MF bodies are pathetic, AF is on par with an EOS 500, Meter Systems are 5 years late, TTL Flash is not really available, the list goes on. I just threw away my Leaf AFI, a total piece of crap, meant to be the most evolved MF Camera available.
If I can have a great modern camera with current features with a current sensor built in for about the same money or a little bit more as a current back with an outdated camera, I know what to choose.
Michael keeps on mentioning how his p65 puts a strain on his shooting technique or his choice of tripod, but that also means, current MF cameras are inadequate. Massive mirror slap, crap AF, no Image stabilising, there is so much room for improvement, it needs to happen on the camera side. the solution can't be a slip-on magnifier for the viewfinder.