Our local campaign ("classic" setting) has been using a variant of Call of Cthulhu/Delta Green/RQ2 mechanics for about 7 years now, along with the "action point" system from Green Ronin's "Dragon Age" RPG. We have a tentative "mass combat" system based on Dust: Tactics, but it hasn't been used yet.
http://asmrb.pbworks.com/w/page/5421...me%20Mechanics
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Michael B.