Some companies (very few) have insurance that allows them to do an SIC checkout. I have a friend of mine who is a falcon rated pilot and does contract work in a 45 for a company based at his home field. He's not typed in the 45. Probably has over 100 hours in it, possibly more, I'm not sure maybe more.
This is the only company that I know of that does this. They are a four acft operator and have had a flight department for quite a while. Only thing I figure is they have had the same insurance for a long time and maybe grandfathered in. I really have no idea how they do it, but I've talked to the CP and he did confirm that their ins allows it. Crazy, I know, but it's true!!
My company does this as well. I don't see what the big deal is. If you tell them you can fly airplanes they expect you to be able fly airplanes. Learn the limitations, learn the memory items, run the checklist. It's the same for every airplane. Besides, quite a few bold face items are the same no matter what airplane you fly. I'd guess that 99% of all turbine aircraft have the same memory items for "smoke". O2 mask - DON, select EMER flow, Smoke goggles - DON, comms - ESTABLISH, checklist.