I found powdered dextrose in a bulk store--labeled "Corn sugar," I think, and with "dextrose" in small letters after.

Nat--Candy corns??? Really??? I LOVE candy corns! Gonna have to go check and maybe get me some!

Also, apparently candy necklaces and other similar (hard, pressed powdery) candies are made of dextrose and maltodextrin. Happy carbing!