It's always fun, trying to second-guess Armortek, isn't it ?
Let's assume a 'tank' has a turret and tracks. So we can discount armoured cars and bulldozers for a start. And we can surely leave out things like the M22 Locust (too silly) and the LVT 'Buffalo' with an M3 turret (fun, but surely limited appeal ?). So the immediate front-runners would seem to be the M24 Chaffee, the M3/M5 Stuart, and the M26 Patton .......
But there are plenty of Shermans that could be done. I'm no expert (but I know people who are

), but what about the E2 Jumbo ? That would be fun. And the diesel-powered M4A2 that was almost exclusively used by the US Marine Corps while island-hopping in the Pacific. It seems a pity to just focus on Europe, Russia, and the Desert.
And then there's the tank destroyers, like the M10 (Achilles to the British) that the German's tried to disguise their Panthers as during the Battle of the Bulge. And the M18 Hellcat, that was highly regarded. Even the M36 with the 90mm gun.
So there's actually lots of possibilities. But for what it's worth (and I'm usually wrong about such things), I'd bet on the Chaffee, because it apparently came a close second to the Churchill for the latest production run.
We'll just have to see, won't we ? Patience is, after all, a virtue .............
All the best,
Chris