The CV 125/2.5 APO was indeed made in Alpha mount, but in extremely small quantities. I have been unable to find one, and given the astronomical prices they have been fetching, probably wouldn't want to pay the asking price if I did.
On another note, those wanting to use Mamiya APO glass on the A900 have two options for adapters. Zoerk makes one, as does Cirrus adapters. I'm unsure of the quality of the Cirrus as I bought one of their Pentax 67 to Alpha adapters to use my 400/4 EDIF on the A900, and it mounted rather roughly, the lens release knob doesn't look too sturdy, and when I mounted the 100/4 macro the lens was facing to the right.
I sent it back asking for a replacement, but I would probably be better served to pay the extra money and get a Zoerk.