Currently on gunbroker.com someone is selling a Mauser advertised as a Colombian-Israeli Mauser (click here). The receiver bears a Colombian crest in the photos. The seller states "my research indicates that this rifle is a known and legitimate Israeli conversion."
The rifle is interesting, but I would be skeptical and ask the seller to document his research. I am absolutely no expert, but I have read many articles online about the Israeli Mausers and never read about anything like this. It could just as well be that someone cobbled together a Mauser by using an Israeli stock (which did have the 7.62 branded into it) and a surplus 7.62/.308 barrel, along with the Colombian receiver. Many of the Israeli Mausers have been parted out, so it is not uncommon to find "Frankenstein" Mausers that use Israeli Mauser parts. Or maybe the Belgian factory had some extra Colombian receivers around, and sold them to Israel?
Personally I would not have an interest in this rifle, but a serious Israeli Mauser collector might want to do his or her homework and take a look.
Update 8/25/12: Sold for $455. Not surprising given its oddity.