Bill,
Sounds cool! I look forward to seeing your site grow.
From Impact, I would press them to re-energize their plans to make upgrades for the Walker Bulldog. They put the plans for the sprocket and tracks (with rubber pads) on hold.
I, for one, would vote to have HL build two variants of the Sherman - both the HVSS and the VVSS. Maybe one is the M4 105 VVSS (I like the Pacific Theater ones

) and the other is the M4A3 HVSS that saw extensive use in Korea. Think they could put dozer blade on the latter?

Anyhow, seeing as so many have waiting to get a Sherman for lack of funds for a Tamiya, it seems that HL would do well to create both suspension and turret types, like they've done with two PzIV variants.
Philip