Ed, have you thought about a lexan rear window? That would shed 28lbs right there and allow you to add some ballast back wherever you wanted.
VFN makes a light fiberglass rear hatch for $246 that weighs 8lbs. It's here:
http://www.vfnfiberglass.com/932001camaro.htm
Jerry Bickel makes a lexan rear window for $350:
http://www.jerrybickel.com/windows-a...-firebird.html