Pixies w/guns is a bit silly. Run Faster does share where in the world Pixies get SINs, and I guess that infers that it will be difficult to play a pixie in most locale, even with a fake SIN. ("really? You are ALL French tourists here in the Seattle Barrens?"
But not counting the difficulty a pixie shadowrunner would have just existing in the Shadows, pixies can be playable magicians. And with a little thought and w/ Rigger 5.0, it's probably easier to make some kind of flying drone with a gun that can a pixie pilot (High Reaction/Agility with Pilot/Gunnery, maybe an adept to boot), or a full on rigger (High Reaction/Logic with Pilot/Gunnery). They could look rediculous saddled up on it, or sit inside to be more inconspicuous (though let's hope that drone doesn't get shot at). They can't default easily, but jack of all trades and high attribute capacity (which pixies have) can mitigate without too much investment. Pixies are smaller than a large pizza, ya? Maybe even a suped up Renraku Pelican could do the trick. It already comes with the storage compartment.
Or a Roto-drone with a little rigger cocoon in a w/built-in trodes?
Edit: I'll add even with Body 1 and Str 1, Pixies with high reaction, an unwared pixie can get their physical limit up to 4 without issue. That's higher than a lot of human/elf non-combat focused character end up getting. 'Wared/adept boosted pixies could be stronger. I know they are small, but stats are stats. Maybe they pack a lot of muscle into those little frames, you know, magic?
Also, I think NeoNet and Evo also give corporate SINs. Maybe they make modified weapons? Pixies aren't going to be able to haul around a gun in a holster all the time like other characters. But like the assassin example, maybe they pull it out of their little pixie bag, set up a shot, shoot, pack up, and go. Trolls get away with using holdouts on the other side of the coin without too much fanfare.
Just playing Devil's Advocate....
