I have two chins in a seperated FN 142 right now, and they seem pretty happy. Lots of room to jump around, room for a wheel, a hutch, a hammock, etc. And yes, they are HUGE in person.
I wouldn't put two in there, but one is fine.
I currently have two in the top portion of a FN 142 and they have plenty of room even with all of the things I have in there. However, they also will be 11 weeks tomorrow so they are not full grown. I have seen people have pairs in one level of the FN 142 though and they never seem overly squished. I plan to open up the whole cage for the girls though once they're a bit older. They're too young for all that cage yet.
Well, the people with the 142 finally got back to me. They want $50(since I have to drive an hour to get it) for it and it's in pretty good shape. Just a little rust. Nothing I can't get off. It's in much better shape then the 141 someone would sell me for $60 which had a ton of rust and the pan was bowed. I figure I'll go with the cheaper one with more room picking it up on Tuesday. Can't wait