There's an innovative solution: A fairly thick adapter clips to the camera body, and the film pack clips to the adapter. I assume that various adapters for various thrid-part backs could also be emplaced, allowing it to work with backs for other camera mounts.
These are the most exciting words I've read about this camera since I learned that the Sinar version would
only work with the (new) Sinar backs and the Leaf version would only work with the (new) Leaf backs.
They inspired the following speculation
Since the thickness of the adapter may well (& possibly by design) be able to compensate for the different mount to
sensor plane distances of already existing backs made for different camera systems, the possibility for attaching
backs made last year and before seems very much brighter. When I think about the use of film backs, especially a
6x6 film back, that tells me that the adapter has to be user removable from the camera side, if it isn't permanently affixed
to the newer backs. It follows the ability to clip in at either orientation is on the camera side. So, it shouldn't be too
technically challenging for even a third party to manufacture adapter plates that are user attachable on both sides that
would allow existing and second hand backs for many camera systems to physically mount onto the camera in either
orientation. Data communication is a different matter. Even if the systems of data communication are electrically
compatible and have the software to be able to talk to each other, features that allow the camera to automatically set
the shutter speed or white balance in an unauthorized back could be locked out just like some resellers lock out feature
of some cell phones. One might have to rely on the flash terminal to tell the back when the camera fires or on an electric
remote release (I can't imagine it being made by F&H and not having at least the potential for one) to simultaneously tell
the camera and back to make an exposure. Hopefully a camera sold directly by F&H like an "unlocked" PDA-phone sold
directly by Palm would be able to attempt to cooperate as much as it could with anything one attached to it. If I was Phase
One, one thing I would seriously consider is a version of this camera that would work from the very first with previous
models of Phase One backs. Since the lack of interoperability strategy has already been employed by the other back
makers, the new camera purchase disincentive for changing brands is already in place, and I imagine their customers
would appreciate having the option to upgrade to the new camera system without the financial strain of having to upgrade
to the latest back at the same time. Being the one digital back manufacturer that has that attitude could make for
great customer relations.
It's really too bad that the digital backs and newer medium format cameras never took to some wireless form of
control communications (like, say, bluetooth for more recently manufactured stuff). The manufacture and distribution
of software based control data interfaces between older and newer equipment would be a lot less expensive than
routing wires through adapter plates that might have to stop half-way at interface electronics for which there's almost
no room. A wireless control data adapter (eg PDA) wouldn't even have to be part of the camera, just near it.