Dave,
I am with you - I think I expressed my thought earlier that there are too many options - one reason I haven't placed my interest as I have no idea what to go for.
In N Gauge the 14-car set is going to be possible and impressive and perhaps a 7-car set also... Maybe as you suggest two 7-car sets (one yellow and one black ended) with less functions e.g. the tilt. Additional coaches (+one power unit?) to expand to a full 14-car set?
I really would like this to happen as well but for me the choice is bewildering and for the likely limited market may mute orders.
Regards
Tony