How about lightweight denim mixed in with all those plaids? I know JoAnn's and Hancocks constantly have sales on denim.
I made a very simple quilt for a guy, somewhat like a rag quilt with lightweight denim on one-side and plaids on the front side, just crazy pieced together. It looked realy neat.
Pretend the plaids are just regular fabric with "normal" designs....sometimes we worry to much about "match-ie" "match-ie" when it comes to plaids. Let them go any direction you want and don't be so concerned about the "lines" of the printed plaids when you sew, either.
Mixing a little solid type fabrics with the colors from your plaids looks great too....Want a really good book with a lot of scrap type patterns, that I think would be perfect. Google Bonnie Hunter and she has some wonderful ideas. Infact, she has a wonky-star pattern free on her website that would be wonderful with plaids. Good luck and let us know what you decide and post a pic or two as you go.