I got a bunch of 1/2" or so SS tubing that I want to use with my brewing
equipment. Anyone got any Swagelocks for said tubing? Does one need to use
SS, or can regular brass work?

Swagelok isn't tolerant of tubing size variation; it has to be
the AISI standard 1/2" O.D. tube to work. Any dissimilar metal
(and brass/stainless qualifies) is a no-no for contact with
brewed products for human consumption. It's likely that
the required ferrule force won't happen with brass parts anyhow.

There are quick-clamp flanges that can be welded to SS tubing,
and lots of support (valves already flanged) so you could make
up your systems to be easily cleanable. An O-ring seal is reliable
at low pressures.