Its certainly something that the what if crowd enjoy. The T-29 turns up in that sort of fiction here and there. I suppose personally it would be more interesting for an Operation Unthinkable scenario, or perhaps for Operation Downfall (though there's hardly any alt-history Japanese tanks out there).
Still, some company must see cash in doing one. Even if its use cases are limited. More German and Soviet vehicles would certainly have a guaranteed market (even if its a niche one). And I'd have to wonder why more companies aren't commissioning Soviet vehicles which may have missed WWII, but seen plenty of use Post-War. That sort of thing would play into the gathering interest in Vietnam and possibly the Arab-Israeli wars.
Ah, but my usual marketing criticism aside (best to keep that to the Weird War board), you've obviously put good work into this.