Digital Backs For 120 Cameras?

In April of 2008 Mamiya announced the ProSD Adapter HX702 which allows the use of the ZDb 22mp digital back on the RB67 Pro-S and Pro-SD bodies.

Note that the ZDb back was originally designed for the Mamiya 645 camera so that's the image size you'll get with it mounted on the RB67.

HX702, $1,499.00 at B&H.

22mp ZDb Digital back, $7,199.00 at B&H.

http://www.bhphotovideo.com/

I found a digital back for a Bronica ETR/SI by MegaVision but its a 35mm format - the sensor measures 24mm x 36mm. Didn't find a price. http://www.mega-vision.com/

I suggest reading reviews of the Nikon D3x. It just might give you the results you're looking for.

http://www.dpreview.com/reviews/nikond3x/

http://www.cameralabs.com/reviews/Nikon_D3x/

Leaf makes digital backs, although I don't know if they have one that will mount on either of the brands you mention.

The fact that they start at $10,000 keeps too many people from buying them, and means most of the support is for Hasselblad bodies.