There were some high line Ladies/step thru frames and bikes but very few were probably sold. Paramount is a great example, these were built to order. By built to order I mean the dealers ordered them. Simple economics pretty much dictated these bikes were ordered in very small numbers as the market was for mens bikes and every ''Ladies'' frame you ordered was one less mens you got. I would guess Ladies models were mostly special order but a what % I would say 5% even there. Frame tubing might have been another issue. Mixte type frames required the long latteral tubes but I dont think Reynolds or Columbus ever made these (at least in the 70s) Were the Tandem latteral tubes available separately? So this left the true step thru designs or a hybrid version which had the upper tube at a shallower angle and a pair of stays connected at the seat tube. I recall Motobecane had a Ladies/Mixte model made out of Vitus . Jack Taylor also built a hybrid Ladies out of Reynolds. I believe most Mixte frames were of the basic variety. Looking back I believe Schwinn Suburbans might have been ordered and sold at a 60% Mens/40% Ladies mix. Varsitys maybe 80/20 and then Letours maybe 90/10. What I remember very distinctly was at the retail level Men would always buy a better bike for themselves and a step lower or more bike for their Wife I also remember the Japanese charged $5 more for a ladies frame but at retail we had a hard time collecting more for them.
Maybe more questions than answers
BOB FREITAS
MILL VALLEY, CA USA