Chaz, I would try SAIC. They are heavily involved in the military science group, but its really dependent on where you are located. Here is a list of the top 50 US military Contractors to get you started.
http://74.125.93.132/search?q=cache...actors+US+Contractor&cd=1&hl=en&ct=clnk&gl=us
Also dont put down Army Science we do alot of cool stuff too. ( Hey want malaria?). If your interested in 3rd world disease research check out the WRAIR (Walter Reed Army Institute of Research)/NMRC (Naval Medical Research Center) labs.
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Covar, i can only answer for the Army side but most Army Research staff are officers (Lieutenants to Colonels, the few research staff that become Generals leave the table to become admistrators). We do have some enlisted staff whom do research for the army but they are almost always support staff and not consider principal investigators.