I agree with you and Grendels, U! Three tanks, on each side, would make it look really unbalanced.
Regarding figures, yeah, it can be tough.
The original figures that Kow-san used when he built his first MaK models were from several sources, but he settled on the old Micronauts, which scale out to 1/20, more or less. By happy accident, that's also a scale that Tamiya and Fujimi use for their professional racing kits, including pit crew and spectator figures. There are some other Japanese makers who make figures and accessories in 1/20 as well, like a company called Modeler's. You can find figures still in production at HobbyLink Japan (
http://www.hlj.com/) (search on "1/20 figures"), and figures that are out of production pop up on eBay and at shows. There is also a manufacturer, Brickworks, who makes figures and accessories specifically for Maschinen Krieger.
Have you ever seen Bryan Krueger's blog or forum? The forum is
http://www.maschinenkrueger.com/forum/, and his blog is
http://www.maschinenkrueger.com/joomla/ Last night I was browsing threads in that forum about 1/20 figures, for some MaK dioramas I'm building. I've got a couple of the figures from the sources I mentioned, as well as a couple of show figures (made and licensed to be sold at shows like Wonderfest, for a single day or other limited time) from Lincoln Wright's Scale 120. I recommend Link's figures highly, they're well sculpted and well cast.
I hope this helps, and I'm looking forward to your next update!