I've been in your place or actually, in the same place. In my opinion here are your two best realistic options.
Option 1: Single Led you put in. Probably the easiest thing is gettting one of the premade aluminum heatsinks that all you have to do is epoxy a led on top of, wire it in with a.) 500mA powerpuck from
www.theledlight.com (others offer it too), b.) plain old resistor (read around here, can't remember who has a really nice tutorial on it) c.) converter board (recommend
www.taskled.com , mainly because you can email the guy who designs the boards (George) and ask very specific questions (battery setup, ect) and he can tell you if this or that works).
Option 2. Malkoff Drop-in. Hold on before you say they aren't available. Starting Dec 10th there may be a significant amount of them available within a week. Email Gene through
www.malkoffdevices.com and have him give you an idea when some can be expected.
My two cents: I am relatively a noob around here too. I waited for a full month actively trying to get a Malkoff drop-in, it was worth the wait. Top quality product and about as easy to install as changing the original bulb in the
M@g. I would suggest for now not using the 6xAA or 9xAA setup...it brings about options that will take a month to figure out (been there done that).
If you build your own (and I encourge you to do so too), be prepared to order this and order that and it could be a month or two waiting for stuff to come from HongKong and other parts of the world. I am at two and all my stuff isn't here yet. There are places you can get stuff from the states, but generally the fine people here that have made stuff available from ideas they have invented themselves, trying to make flashlights better, are not as a rule full time flashlight parts makers, they have real jobs that unfortunately keep them from full time flashlights, much like me.
I strongly recommend if you can get a Malkoff drop-in do, if nothing else as a piece of engineering for you to meet but probably not exceed....it's that nice. So look for a heatsink, emitter, some artic allumina epoxy and some sort of device to regulate current (resister, puck, or board.....the puck and resistor should be very, very easy and straight forward) and get your order in and if your lucky everything will arrive at the same time so you can druel over Malkoff's drop-in while you make your own.
Good luck, and post pictures. We all like to see what anyone is doing....no matter how simple or complex.
Bob E.