There are different classes of lights and they are meant to be different in size as well.
In my eyes, the Raptor-0 is the small class. It is great that an AA extender (which I didn't order however) is offered and that you can use a NiMh or even a 14500. The light gets slightly longer of course. I'm fine with the CR123A and RCR123, even if a 14500 is supposed to give longer runtimes than the RCR123, I always have enough spares with me to cover my needs.
The Raptor-2 is a bigger light and takes the 18650. It'll give longer runtimes while I don't know about the difference in the beam, as I don't have the RRT-0 yet. While the brightness is about the same nowadays on a lithium based cell, it is only the runtime and the size of the light that make them different.
If Jetbeam would offer an 18650 body for the RRT-0, I would go one step further and tell them they should only offer one light anymore, with different options for the head and the body. Complete lego to say it right, everybody could pick up the options he would like. If they want to stick to different classes however, the AA extender is enough option.
Just my thoughts, european car brands like BMW or Audi have been going the way of different possibilities in each class for a few years now. While you always had model A for the small class, B compact class,C middle-class and D upper class, you currently can have model A even as a break while they also offer D as a coupé and everything in between, complete modulation. So, in terms of space for passengers and/or luggage, the small model in the big variant maybe almost the same as the big model in the small variant, but they are completely different. That would be an RRT-0 with an 18650 and an RRT-1 with an AA. Weird in my eyes, but there are people who want these configurations, up to the manufacturer to find out if the demand is big enough to give it a try...
