Re: My SL4AA = gone... buy another, or something else?
Yes, you can have a Seoul P4 in your ProPoly 4AA or 2C. It takes a bit of patients and a rotary cutting tool, but it is not that difficult if you have some modding experience.
I created a thread a while back here:
http://www.candlepowerforums.com/vb/showthread.php?t=149149
By exchanging the Luxeon Star 1W LED with a Seoul P4, the brightness is extraordinary! Everything focuses like the original Luxeon (with the copper spacer), and the beam really does not widen any. You can purposely de-focus the LED if you want to get a softer beam, but you would have to experiment with that.
However, I do not think that you can get a Cree XR-E to work. The aluminum reflector will not focus with the XR-E due to that metal ring. The beam probably would not be as good though since the XR-E uses that small glass lens. You could pop off the lens and metal ring and it would focus again, but you would have to search the forums on how to safely remove the lens stuff (it is out there, but I do not remember where and by exactly who -Newbie?). If interested, I can search through old bookmarks for you. Just PM me.
Handlobraesing, I would get another. Though it can be a bit bulky and not the brightest, it is tough, has good runtime and a nice beam, and it is not that incredibly expensive. Matt Sutton has a good point. You could try the 3C version. It is even more bulky, and it has an awkward clip, but it is brighter and better in a way.
Well, I hope someone you know comes across your light. You should put a small paper identification tag with your name and phone number inside the battery compartment. Well, good luck!
-Tony
EDIT: Oooh, nice new CPF editor! Anyway. I just wanted to add (since I was too slow to type) that you will not destroy the head assembly with special, shallow slots if you do it right (not too hard at all). Yes, the pliers, straps, and boiling will not work (without damage). Also, the stock circuitry does just fine whether you use a Seoul or Cree. It powers the LED, depending on the Vf of the LED, at around 500mA. You can lower the current or even raise it to about 700mA with a hack that we came up with. You are just increasing the luminous efficiency of the light by using the Seoul (or Cree). You could change out the circuitry if desired and use a Downboy driver (pretty tough) if you want even more current, or but it is not necessary.