I hope the truck skirting will be removable, if Kato chooses to model the as-released version. I'd prefer to modify the train to a late-50s version, sans skirting.
As for E6 and E7 shells, Kato would be silly not to. The number of paint schemes they could sell on those two is pretty significant, not to mention the trains they might be able to package with them with a few new cars here and there. Broadway Limited be damned; I'd rather give my money to a company that bothers to make the passenger trains too, not just the locos. I'd say something about BL's time to market too, but am not sure Kato's not that far behind. Let's hope Kato's recent spurt of activity is a sign of the future, and that more trains and more re-releases of old models will be the future.
I keep hoping for a late Hiawatha too, complete with super dome and Skytop observation and, dream of dreams, a Little Joe to offset Kato's obvious eastern railroad bias announced with its GG1 model.
