I used Owens Corning 703 rigid fiberglass, that I picked up at a local insulation company that sells to builders. After building some easy DIY frames, and locating some black stretchy material like speaker grill cloth at Wally World (sorry Tom), I was good to go.. page 1 and 3 have pictures of the superchunks and first reflection panels.

http://www.axiomaudio.com/boards/ubbthreads.php?ubb=showflat&Number=144079&fpart=1

M80s VP180 4xM22ow 4xM3ic EP600 2xEP350
AnthemAVM60 Outlaw7700 EmoA500 Epson5040UB FluanceRT85