There does seem to be a gap from SF, where other companies like Fenix and HDS have stepped in. Some CPF'ers have chosen to mod their KL1 and KL4 heads, putting the KL3 3watt LED into the KL5 reflector. I have heard some chatter here about putting the 5watt KL4 LED into the KL1 head w/ the optics, but I haven't heard anything concrete. The only issue I think that might come up would be heatsinking problems (that is, with a 5watt inside a KL1 head). But, since the LED's don't send their head forward as incans do, I'm not sure if this would be an issue or not. I'm definitly not an expert.