John Shriver , Jan 19, 2007; 08:52 p.m.
Pentax bodies are a millimeter thicker than Ekakta bodies. Also, the diameter of the lens mounts is almost equal, so an adapter would probably have to be 8 millimeters or thicker. Very macro.
There are adapters for both Pentax (M42) and Ekakta for the old Canon breech-lock mount. Canon AV-1's are dirt cheap, fine cameras, and being aperture priority auto-exposure, well-suited for "preset" lenses. The Exacta adapter (Canon Adapter E) is moderately scarce, might well cost more than the AV-1!
There's also an Exakta adapters for Minolta and Konica SLR's.
Of course, there are also Exakta adapters for Olympus Pen F, and 4/3 System DSLRs. But these both have "serious" crop factors!