It reminded me of some research I did last spring. A friend wanted to donate hair, but it wasn't long enough for Locks of Love's 10 inch requirement. So I started searching for other alternatives.
I found 3 reputable organizations that use donations of hair to make wigs for cancer patients. They have varying requirements for lengths and they serve different sets of clientele at various costs.
Beautiful lengths, www.beautifullengths.com = 8inches
Locks of Love, www.locksoflove.org = 10 inches
Wigs for Kids, www.wigsforkids.org = 12 inches (this group is the favorite of my friend who works for American Cancer Society)
If you know of other groups, I'd love to hear about them!