I'm thinking of a stop-gap alternative until I can get the 3D design for the Kadee mounts for the Amfleets finished... One is a down & dirty replacement for the stock "claw" couplers. this would keep the truck-mounted design with a scale-ish coupler head and is non-functional. It would be considerably shorter than the stock couplers, and the pulling faces would be at the ends of the diaphragms, so they would touch. At this time, functionality on passenger cars isn't a high priority IMHO.
With that said, I'd like your opinions and thoughts...
Accurail in HO scale sends dummy knuckle couplers with every freight car they sell. I use to run a 25 car coal train with these couplers. Never had to worry about cars uncoupling at all, next time you visit a hobby shop look for white or yellow boxes. Coal cars was a molded one piece, other cars was a molded two piece.