I don't think the pellet kamado will sell very well. Kamado cookers are very stable and do not need a temperature controller at all. Why would I want to burn pellets in my kamado when I can burn wood and lump and achieve rock steady temps for 15 hours easy.
If anything I believe an external pellet attachment would be great for gas grills. You could probably target people that live in condos or gated communities where charcoal is not allowed.