I am often very interested in creating an army that can be "Dual Use." The idea is that you create an army that can be used for two different
codices. Often my ideas have centered around adding an imperial guard contingent to space marine forces. In a perfect world I would have enough money to create a steel legion army.

They look great. They are darkly
Gothic. Organized enough to work as regular
gaurdsman but menacing enough to look like they
could be chaos. I would play them as
auxiliary units to both my Wolves and Alpha Legionaries. But then I
realize that
forgeworld is ass-expensive and I would probably pay more in
ship
ing than a normal army costs.
A friend of mine beat me to the punch on this though, he used
warhammer zombies to create A LOT of "counts as" lesser demons (like 70 of them). After creating so many he
decided to try them out as
plaguebearers in a codex demon army. I haven't played against it yet, I will be interested to play against it.
Some other interesting ideas have been popping into my head, though, about how to get more out of some of my units. I recently purchased a renegade militia
conversion pack to make a squad of cultists.

I used them as "counts as" for lesser demons. Works great with the fluff as Alpha Legion are
alot more likely to utilize cultists than demons (I gotta give credit, though, it was a random guy at a tournament that gave me the idea). While doing it I
wondered if I
couldn't expand the force and create a renegade guard army and supped them as
cultists for my larger Alpha Legion force. I might have to do more investigation to see what that army would like.
Rix