Depending on demand, further sets will be added. Maybe we'll even develop the range into the later part of the war, when Romania fought as part of the Allies.
Might I suggest that rather than branching into esoterica, with things like vehicle crew being adaptable from existing models, you might be better off getting some variants of the basic figures done. Puttees for some and I'd suggest getting some head variants and leg wear modifications to cover the mountain troops who were Romania's elite forces and saw action in all of their campaigns. Who doesn't like a figure in a silly-large beret and rolled socks?
Frontier Guards would be a wholly different topic, too much variation for the early ones, helmets, weapons etc.
Of course if you ever did decide to go silly and produce exotic stuff that would be unlikely to sell then Romanians in greatcoats, sheepskin lined capes and those distinctive fleece caps would be nice. Ideal for use as a speed bump outside Stalingrad circa November 1942.