Well, I've been looking into building a costume for a while now, but only recently have I done any looking around for stuff.
I'm still in high school, so I can't exactly run out and drop $100+ dollars on a Blackhawk vest, so I've been looking for a as-canon-as-possible, yet cheap vest and I found one for under $50 dollars. It's the Condor Deluxe Tactical Vest.
HERE is the link to the cheapest one I found so far.
It's pretty much canon stock, but with a couple minor mods, it would probably be completely canon.
Anyways, just thought I'd share. Oh, and I'll be sure to post pics of things, once I start purchasing.