I got PMC drawing from Dmass, this will be similar to gyro's steel PMC. I'll submit the work to machine shop soon.
The drawing is on svn full PMC assemble can be found at ATF:1543.There are spare mirrors in PSL that can be used. I still have to look for a PZT.
The round trip length is 0.33 cm. this corresponds to FSR = 454.45 MHz. If I want to be able to scan through 2 FSR, the displacement range of the PZT will be dL = 2*FSR * L / f, where L = 0.33m, f = c/lambda. dL ~ 1um.