Some suggested units:
French Bomber:
http://en.wikipedia.org/wiki/Breguet_14
French Cavalry should look like these:
http://www.hat.com/Curr3/Bx8272BC/Bx8273FC.html
Regarding infantry, why not make the opposite type to that provided in the game re: Early or Late war model, particularly in regard to steel helmets? The late models can be used for “Stormtrooper” rules, or “Veteran” units.
So, for the French, provide early war types with Kepis such as:
http://www.hat.com/Curr2/Bx8148FI/Bx8148FI.html
You’d need early war: British, French, US (Montana hats?), Italians
Late war: Russian, Germans, Turks, Austrians (stahlhelms)
I’ve suggested elsewhere that 3 sets would cover most units vel:
1. French, Italian, Russian (maybe Muramets bomber?)
2. British, American (Whippet tank, Sopwith Camel, Handley-Page bomber)
3. Central Powers (A7V tank, Albatross, Gotha bomber)
since each of these groups used much of the same equipment.
For example the “Central Powers” sets could be the same pieces made in the 3 appropriate colours, and maybe a light grey for Austrian green haters. Tan set for alternative Turks?
Also, a French set in paler “horizon” blue might be popular.
To supplement the UK set, Anzac, Indian and Arab irregulars; the Indian infantry could also be used for WWII.
My own suggestion for a new unit type is the Askaris (native African infantry); either in the appropriate colours for UK, F, G & I, or a generic unit (in black?) which can be recruited by any power owning African tts.
I don’t think you do decals, but that would be a nice touch.
Also:
The sea mine pieces in two colours (red & blue?)
Revolution markers
“Anarchy” marker? (for tts that have fallen out of any power’s control)