http://www-personal.umich.edu/~mule/smurfgen.html
I took the liberty of trying a few myself:
LordSmurf = Deadly Smurf
Allaboutduncan = Kung Pao Smurf
Mark = As-Seen-on-TV Smurf
CP32 = Critically Ill Smurf
Dan D. = Radioactive Smurf
Ahmed = Pimpin' Smurf
Greenranger1 = Pimpin' Smurf
Dajizzarizza = Transparent Smurf
DCUcustoms = Phlegmy Smurf
Jowins = Erotic Smurf
James = Pantsless Smurf