I admit to being a confirmed 15mm gamer but the Interbellum Imagi-Wars has me seriously looking at 1/600th and
Oddzial Osmy's great range of 1/600th miniatures.

There's something about the miniatures meets
Panzerblitz that appeals to me, and I can easily play divisional size actions using Chris Kemp's excellent
NOT QUITE MECHANISED or Tim Gow's
MEGABLITZ rules. Even if you don't want to play these rules, I recommend a gander at Chris' Eastern Front
org charts for the Italians, Hungarians and Romanians. Perfect middle European fodder if you are searching for Orbat ideas without falling into the trap of creating Ruritanian Panzer divisions.
What I like about the Oddzial Osmy range is that the Polish range alone includes infantry, cavalry, tankettes and a whole heap of Vickers export models. In this scale it's both economical and practical to get them ALL onto the gaming table in the same scenario. Of course we lose the character of the uniforms but this can be made up for in the character of the formations and major equipment used.
If you are interested in the potential of 1/600th, look at the Polish, Italian, early Russian, French and some of the early German models.
Attractive and effective terrain can be scratch built very easily or bought cheaply from Irregular Miniatures as this photo from their website shows:

So, I may opt to continue playing Interbellum Imagi-Wars in both 15mm and 1/600th to get the most out of this fun gaming genre - and to fill in whilst I wait to see what
Flames of War bring to the party with their planned 15mm Early War releases this August.
CheersMark