A universal bellows unit, the BALPRO 1 Universal Bellows from Novoflex allows the use of most medium format cameras 6x7 cm and smaller (only with focal-plane shutters) as well as most 35mm system cameras(digital OR film).
With the exception of the Canon EOS system, you'll need 2 or 4 adapters in addition to this bellows to use the system; medium format camera systems require one adapter to connect the lens to the bellows, and one to connect the bellows to the camera. Systems based on 35mm camera designs (except for Canon EOS) requires 4 pieces; the APRO & PROLEI adapters plus a lens-system-to-bellows adapter and a bellows-to-camera adapter. The Canon EOS system requires 3 additional pieces, but also has the unique distinction of retaining all aperture communications between the camera and the lens. All of the combinations are listed here as recommended accessories alphabetically by camera system, with the bellows-to-camera adapter first and the lens-to-bellows adapter next.
Thanks to a complete system of adapters, combining different lens and camera systems is entirely possible. So you can not only combine most medium format lenses, but also nearly all KB lenses or special lenses with camera bodies in each size up to the 6x7 format. Novoflex even has three large-format-type lenses which permit infinity focus.
The BALPRO1 features a long Arca-type quick release base that fits into any Arca-type quick release mechanism, and three 1/4-20" & 3/8"-16 threads upon the base.