Paintress,
I'm sorry to be blunt, but let's cut to the chase.
At the moment there are two MF product lines really in production, Hasselblad and Phase One.
- Hassy has a very integrated shooting product, let us say a super-SLR that can take loupe 90 degree finders.
- Phase One has a less integrated camera/back combo but its software is very polished and many love it and swear it gives superior results.
- AFAIK backs from both bundles can be unmounted and remounted on a view camera, with the right adapter.
- There is also a Pentax just appearing on the market.
The Hasselblad H4D31 is about 10KEuro; it's an old chip, but should work well to about 200/400 ISO, and is superb at around 50 ISO. I am sure Phase has something similar. From there you can climb up to 60MP on Hassy, and 80MP on Phase, usually by trade-in.
There are also a variety of dead systems (Contax) or zombie systems (Rollei/Hy6, Leaf, Sinar) ghosting around. Many of these are superb, with zillions of Zeiss lenses and working bodies to be had for a song, but if you don't know what you're doing and don't have a friendly dealer or repair shop they may not be a good idea.
Edmund