Have you checked any of the online 'Usual Suspects' (Casablanca reference)?
Midway USA, Cheaper Than Dirt, CDNN, or even checking Ebay?
You can also call Kel-Tec Sales directly. I say call, rather than using the online store, because the online store defaults to shipping UPS/FedEx, where if you call, they usually will ship via USPS for a LOT less.