I think frames still get taller quicker than they get longer, on the basis that my seatube+post length is about 26″ (about 18″ + a reverb)and wear 32″ trousers, anyone with a 21″ frame (STATO) and a reverb must be 35″+?
Working back from that, assuming a 4″ minimum insert on a 16.5″ seatpost, that means the person that bikes intended for with the 35″ insde leg could just as easily ride a 16.5″ frame.
So whay are frame sizes not;
16
17 (but as long as an 18)
17.5 (but as long as a 20)
18 (but as long as a 22)
?
Surely if you can package the suspension into a 16″ frame, then the forces/loads are all sorted as the back, it could even save cash by only needing one seatube size. Might just need to brace the headtube a bit better as the TT/DT angle is narrower.