Cannibalizing a crampon - safe?

Seems like it.
Awhile ago I posted about my Grivels wearing faster than my old BD contacts. The problem is that my BD's are strap-ons, which obviously isn't idea. So the problem is: do I want to buy a whole new set of BD crampons? I wondered. I began looking at the construction of the two and realized that the block at the back of the crampon that locks the boot down appears to be interchangable between the two companies:

Apparently the rear part of the BD Contacts were designed so that they could be used interchangably in the factory for the entire range of crampons they were making at the time. I just popped the rear block off the Grivel and then popped it into the holes on the BDs, then adjusted the tensioner until it fit the boot.

Anyways, this seems pretty safe. The boot is locked in really tight in the above picture, as secure as the Grivels are normally. Now I just need to cut the rubber part off the pop rivers on the back of the book, and maybe remove the pop rivets too. Has anyone ever tried this?

yes, not a big deal so long as the parts fit well. People swab toe bails and heel levers between brands and models all the time. 

Yea, go for it. It is commonly done as Graham said. I made a set of Petzl Side-Lock heels into normal lever-lock heels this past winter, just cut the tabs off and used a grivel heel lever.