I think the J26 tank would be an interesting comparison with the old TMD/SSM design, and castings for it might be available as a pack from Des at SSM. And yes, the facility to build it in 21mm gauge is important.
Wonder what the price would be?
There's nothing else in that list that interests me, I'm afraid, unless Roger has a sudden hankering to produce a K1/K1a, 400 or 500 class!