With regard to the 00 quadart set, are you going to produce and "all third/second" set, a "composite set", or both? I've had a thought regarding articulation of these coaches, that would enable a protypically close spacing of the coaches, while still being able to negotiate unprototypically tight curves. A cam machanism such as that used by Bachmann, Hornby, ROCO et al for close coupling with NEM boxes, could be designed to enable the coaches to share a bogie while alomost touching on straight track, but their outer edges would move appart on curves. This would enable them to get around tighter curves, without the need for a huge gap between the coaches, at least while on a straight.