While I certainly don't discount the role the Matilda played, in terms of sheer numbers and variants produced as well as it's centrality in the service of its native country's military, I don't think it's in the same category as the Panzer IV, T-34, and M4.
Sorry Michael, I realised that the numbers built was a key element on what was proposed.
My post was more in jest; a play on your "there at the start of the war" comment, as the Shermie was not around in 1939. I should have added a to highlight that.
I've a few other builds I enrolled for, but depending on timeframe and my progress, I would be interested here too. I have at least one kit of each of the 3 in my stash.