I recently found and purchased an antique Ray-O-Vac flashlight/lantern. For a fun and useful project, I'd like to convert it to a very bright modern lantern using 18650 Li_Ion battery technology. But to start the project I need to determine a bulb and driver to use. I am all but totally ignorant on this subject and need help determining what to get. I hope I can find some help here. So, thank you in advance.

Here are my high-level desires:
1) I would like the light to be as bright as reasonably achievable without breaking the bank. (The case allows for plenty of battery and the bulb housing is such that I don't anticipate heat issues.)
2) I would like the brightness to be variable, with at least three steps, but more would be better.
3) I would prefer to not have strobe and SOS blinking.
4) I would like a last used brightness memory function, if possible.
5) I would prefer to be able to use just one bulb, although I'm not totally opposed to using a multi-bulb assembly.
6) I am thinking to mount the light(s) and reflector(s) in the lantern's bulb housing and the driver(s) in the case - although if that is a bad idea then let me know.
7) If it is possible to toggle the different brightness settings by using the original switch on top of the handle, that would be best. As much as possible, I would like to be able to keep the original appearance of the lantern and not be drilling a bunch of holes to accommodate the project.

So, that is the project. I will appreciate all the direction provided. I do not mind doing my own homework, but I really do not know where to start.