How 'bout this? A Wal-Mart special:
From Wal-Mart:1) Large disposable turkey roasting pan - $0.97 2) Rubbermaid clear lasagna (plastic) container $1.97 3) Gorilla tape $9 (!)
Cut the corners on one of the small ends of the turkey pan. Mount your router in the lasagna pan with the antennas poking through the end of the container. Place the plastic box so it overlaps into the turkey pan with the antennas (mine are longish 9dbi onmis) evenly spaced (3/4") from the inside of the aluminum pan. Mount the whole assy on a mast (with screws and Gorilla tape) and attach to a Radio Shack TV rotor (in my case on a 20' mast for now).
The thing friggin screams! I'm picking up one AP at over 2,000 feet away....
God I do love messing with antennas - I guess it's the ham in me.