After 50-something years in business Grimeca has closed their doors and filed for bankruptcy.
FYI, the eye-to-eye on the mounting holes is the same as the PM 162x2 and the 125x4 calipers so you can use their bracket. Ran one of these on a rigid about 10 or 12 years ago and I thought it worked well and looked pretty neat. Nice alternative to the original one piece, cast PM caliper.
Oh, and if I remember correctly you have to either drill out and re-thread the PM bracket to a larger size or find/make new mounting bolts, which was pretty easy on a basic lathe (the mounting holes in the Grimeca caliper are bigger than the similar PM calipers... or were they smaller? I don't care).