My last few were through amazon from midwest hearth. It is Applied Ceramics online store according to the guy at applied ceramics. Last I heard, applied ceramics is the OEM manufacturer for BK. Price was very good, gasket included was wrapped well and taped. The princess cat is available in ceramic (OEM) or stainless steel. After trying both I have no desire to waste extra money on the stainless. It's just more likely to clog and had no noticeable decrease in warm up time. Same life in hours.
Here's the link for the princess cat. Unfortunately the king cat is quite a bit more money.