I like the idea of the add-on modules. And regarding an Eastern Front module, as long as the Axis side remain the same as a corresponding Western Front release (eg - Bagration would be a good one, being roughly simultaneous with Overlord), Eastern Front would be a marketable proposition, wouldn't it...?
(plus a number of Soviet vehicles - halftracks etc - were lend lease)
I bought 2 copies of CMBB, one for myself, one for a buddy, if it helps you guys market an Eastern Front module, I promise to buy 3!