That's a great lineup of PV's on the desk. I started this thread, and checking back on it I am happy to see so much discussion, 26 posts so far.
In answer to David's question about the difference between 16340 and 14500 batteries. I have both sizes in AW LIMN's at the moment, of around the same age. The 14500 is rated at only 50 mah more than the 16340. Yet, the bigger battery seems to provide a little more kick and slightly more duration. However, I was using 510's on the P 16 and 801's on the Super Six, both in LR, at the time. So, it's going to be different.
Here, I must also bring up the issue of air draw. The Super Six will always set the benchmark for me, because its adjustable air draw is unmatched, when not flooded. So, that is why I believe that a potential 14500 mod would be a great place to incorporate some sort of adjustable draw, a top switch, and perhaps even venting as standard. That top switch would shorten the unit, making up a bit for the longer battery.