I'm not sure if Rubicon pays attention to this forum anymore, but I decided to keep track of the products they've announced at some point that I'm waiting for, money in hand, ready to order a few of each as soon as they're released:
Soviet BT-7
German Panzer I
German SdKfz 234 series
US medium tank M3
French Renault FT
I might also buy one Breda autocannon to check it out. Although I'm not keen on earlier crew sculpts, some of the more recent kits have improved in that department.
Some of the early war vehicles I am still hoping for:
Redesigned Soviet T-34 kit that was planned but dropped
Soviet BT-2 and BT-5
German SdKfz 231 series
German Panzer 35(t)
Italian L6/40 and its derivative, Semovente da 47/32