New question:
Alright I've been doing some research and i think i need only one more answer now. Where would I put the negative contact of the driver? Since the positive one would be on the metal thing.
Last I checked Hightechdealz sold 9v connectors for $0.50 or so. You can use a 9v, but it won't last for a long time. I would get a labby heatsink from modwerx, they're about $21.
To UNfail it may be best to open a single thread, (choose one you have already opened), and let all the other ones die off as this will contain all your questions in a coherent sequence that you can look back at easily.
It allows those kind enough to help you to keep track of your progress; know how you have been helped previously; and doesn't fill the first page in the section with threads started by, 'H3llk03r'.
It is not good etiquette to post a new thread each time you have a question when you have similar threads running. Please keep to one thread and spend a little time reading and searching for yourself. LPF helps those you help themselves... One thread at a time.
Maglite: not a good idea. You need something to hold the diode and module in place (heatsink). In reality, the space inside a 2xAA maglite isn't big enough to do that plan, I believe...
EDIT: and where's the switch? the original one would be hard to use unless it's a tail switch.
The essentials are nearly correct but you'll have to figure out if it'll all fit into a maglight of your choice, although I think Charlie is right. Given that the RCKSTR requires ~2.25V above the diode voltage then ~5.5V + ~2.25V is ~7.75V. Fully charged to 4.2V these batteries will provide 8.4V so yes, you can run the module from these batteries. At their rated charge of 3.7V this only give 7.4V but you should be okay with these as a power source. You need to look at your +ve and -ve connections to the module. You can choose to use the case of the host as a path. This is commonly done and depending on which contact goes through the host determines which way you insert the batteries.
However, this really should've been posted in, "Advice Please?", thread that you have already opened and is directly below this thread as I write. As your build progresses people will see the thread return to the top of the page and know new information or a new question has been asked. This interest in seeing you progress will invite readers, (and contributors), in. Continually posting new threads will alienate people and your threads will rapidly be ignored or flamed. This is the second thread you've opened with this same title in two days. I have tried to tell you about this but it probably won't be me the next time and probably not so politely either. You have to pay attention to this advice. It will be noticed. I'm trying to help.