I know a couple FOH engineers with deals from Shure and others, and if you pick up Mix, EM, EQ etc. you'll see gear ads with engineer/producers all over them. It's definitely tougher as a studio engineer since you don't leave the hermit's cave, and don't have the visibility of a touring musician, but the right person at the right time for the right company may be able to put something together.
I also know loads of musicians and bands (as one might expect, working in this industry) with deals anywhere from a bunch of major free stuff that keeps showing up that they don't know what to do with, to a wholesale purchase deal. I got one of the latter just by calling and asking, though I had a contact person given to me by another artist on the roster. Still, if you can offer them some kind of visibility or benefit, a company may at least give you some accommodation.
High-end Boutique audio gear, however, is tough to get, as are some of the more in-demand or established companies, whether audio or musical instrument. A new company with a product they want to get some in front of some eyeballs is your best bet, though new companies can't afford to simply give a bunch of stuff away, so it's likely to be a limited deal. Also, it's better to do it at a time when you have something going on, like a tour, or a current project with some visibility, or an upcoming album with a known artist.