I know this is late, but it's relevant. Schipper is now actually making the Romanian uniforms. All you gotta do is send him the money, and you too can do an "alternate" impression.
To tell the truth, "alternate" impressions are even more fun than so-called standard impressions. Of course, for me, the fun is the hunt for the stuff. Getting to wear it at an event is just icing on the cake.
So far, my "alternate" impressions are:
1939 German infantry (the stuff is relatively easy to find, if you know what to look for, and are willing to dig around. it's also a lot more different from '44-45 stuff than most realize)
1939 Polish infantry (Schipper and Armia can kit you out with about 80% of what you need)
1940 British infantry (relatively easy and relatively inexpensive if you look around)
1942 Romanian infantry (just starting out)
I'd love to do 1940 Dutch. I think that's a really cool impression, even though some events would last longer than the actual period of combat.

The trick is, nobody will make/sell the stuff if nobody asks for it. Major kudos to Rob Haught for propelling Romanian forward. He wanted Romanian to happen, so he
made Romanian happen. I am trying to push 39/40 German specifically, and early-war impressions and events in general without much luck. Fortunately for all of us concerned, Rob has a lot more energy than I do.