Where could one find prom dresses with a camouflage theme?

You will not be able to actually find camouflage bridesmaid dresses off the rack. In order to have them you will have to special order them from a bridal shop. The other option is to make them yourself.

Camoflage bridesmaid dresses are also available online at the following websites:

CamoFormal

RealTree

CamoDivas

eBay

Amazon.com