Roman Apparel's The SOLD Project tee shirt is one good piece uniquely designed for the cause. This crème color tee is featuring a beautiful watercolor design which evokes a feeling of childhood innocence; although my only worry is back tag of the shirt (says "sex sells. children. for $10 billion a year".) might be misinterpreted by those who don't get it at first sight.
The tee is sold for $32.00 each, with half the proceeds going directly to The SOLD Project education fund and the rest (oh yeah, there's still $16 bucks) being applied to printing costs. You can find out more about the SOLD Project to watch the heartbreaking trailer for their upcoming documentary (QuickTime Player required)