Just a thought... howsabout a scenario set around the invasion of Russia in 1941? Because we don't have a decent early-war plane set, we'd have to have some substitutions, of course, perhaps using the Dauntless and C202,C205 and mebbe A6M for the Russian fighters, the Ki67 for the Pe2...
With a good terrain (plenty of vehicle bases, few air bases, fewer large air bases) and rules (field capture by ground troops only, 1 air life per frame...?) and judicious choice of GVs and numbers for each side (many more Russians than Axis, but Axis with some equipment markedly superior) I think it could work well. Kind of "Niemen in reverse"... :-)
Speaking of early war plane sets, IMO the few most vital planes we're missing are the He111, the Wellington, the Mosca/Rata, the Pe2 the SM79 and Fiat G50. Oh, and the B25 Mitchell (the C variant of which makes a fair Do17 substitute) The Ju52 would be a good addition, as would a light tank of some sort (my vote goes to the BT7, or failing that, the Crusader), and artillery.
Given the above, we can fudge scenarios right from the Fall of France through North Africa and the early days in Russia. Add in a lightly-armed (guns) B17, and you help out early PTO, too.
Only other stuff I'd seriously like to see that'd help scenarios out involves seaplanes, recce/utility planes (Hs126? mebbe a Storch?) and biplanes, and HTC said "no" to the latter some time ago... :-(
Esme
