If you have a newer model maglite (“C” in the serial number), then this sort of thing should work:
(haven’t used them, but just googled maglite and the part number)
If it’s an old mag and you can’t find it online, then sometimes you can find people here or CPF that are willing to sell stuff.
If the link above includes the ‘barrel’ that you don’t want, then I think you’re up the proverbial creek, as I’ve never seen the switch itself done separately. Mods usually involve mangling the entire assembly, so you’d probably need the whole thing.
For the driver for the cree you’re talking about, it depends on the emitter (1 or many, parallel or series) and the voltage you want to feed it. Usually, 1 lithium ion battery and 1 emitter can be direct driven, but you won’t get modes.
To make a multimode driver work through the mag switch, you probably want to convert it to be a momentary switch. Our man OldLumens can help you here: Side switch host modded to momentary only?