Regarding Vietnam, aside from Caribou and Buffalo (which USAF got killed), don't forget Armed Mohawk.
Although Congress does love the Marines, I think thre's more to it than that. They got the CH-53K for the same reason they got the CH-53E: Army can't get its act together on a heavy lift helicopter, so Marines were given permission to "modify" their existing aircraft. UH-1/AH-1 were wearing out, and the Y & Z were thought to be easier and cheaper (Orignally most Ys were to be mostly conversions, but the rate they were wearing out plus with Afghanistan and Iraq, they couldn't afford to have that many out of service for the time it took to convert. Most Zs are conversions, but new production was added for pat of the total for the same reason as the Y and to make it a viable potential candidate for export). As for the F-35, the B is essentially the A with the lift system. The Marines actually get a more capable plane than they asked for, and USAF gets a larger production run to help hold down its costs. So, they're good buddies on this one. Regarding the V-22, they originally were to get 552 (it was to do more than just replace the Phrog), so they've taken a big hit there.
Regarding V-22 sized, remember that USAF didn't like the idea of Army SEMA V-22s flying around in "their" airspace, and AH-56 was a lot smaller aircraft [and a helicopter(!)] that dared to be proposed for CAS. The 1965 directive banning Army having armed fixed wings is still in force, and Tilt-Rotor looks like (is) a fixed wing.
I hope this time we'll do better, but C-27J gives me pause.
