The biggest problem we intermodal modellers have been whining about for awhile now is the lack of 53' chassis to haul our neato 53' containers. Athearn doesn't seem to be interested, and none of the other manufacturers out there are either. There is a kitbash workaround using the adjustable Walthers one, but other than that, we're limited to the shorty 20's that Athearn makes, plus a 40 and 48' ones from Herpa. I've seen an extendable from American Ltd, but don't know if it's still available.
Kennedy