You're right JoeN, I can't find them either.
Only on e-bay. Lots of 5 & more.
These are in Niagara Falls, NY
http://www.ebay.com/itm/5pc-Worldsemi-WS2803D-18-Channel-RGB-Constant-Current-LED-Driver-DIP-WS2803-PWM-/150694768407?pt=LH_DefaultDomain_0&hash=item23161baf17
Same seller also has lots of 10, 25, 50, 100, with price dropping with qty.
Surface mount also.
Wonder how they got to be sole distributor>?
Digikey,
Mouser,
Avnet,
Arrow,
DipMicro,
Tayda,
Jameco,
Gerber Electronics,
Newark,
Future Electronics,
AllElectronics,
SurplusSales,
no one has these.