I don't post much, but I find a need to jump on this one.
I'd love to see a Precise 14500.
That's not to say that there is anything wrong with the other battery options, but I do think the 14500 has a place in the line-up (especially with the new AW IMRs).
Yes, I have a P10, P16, P18 and S6 and all are wonderful - Dave's quality is awesome. Based on the having it for (almost) a week, I think I like the P16 the best - but the others still have a place (for various reasons) in my routine. I'm glad I have them.
I think a Precise 14500 would be approximately 16.5mm x 85mm based on the other Precises. Thinner and shorter that the S6 and yes, longer, but thinner than the P16. That would be great and I'd jump on one in a heartbeat.
Why? Mostly a matter of personal preference (and the best quality device(s) available).
Keep up the good work David.