I'm going to order an E1L here shortly. I like the size. The only thing that I don't like about it is the regulation isn't that great as shown at flashlight reviews (scroll down):
I'm wondering if it would be possible to upgrade the emitter to the highest U bin out there (UV1L?) to improve the regulation off a primary cell. Would it?
I've also wondered about the regulation/runtime with a 3.7v RCR123 (protected or unprotected?) but nobody seems to know. Any comments?