I just bought a gun from the Arms Locker with Bitcoins. Turns out I'm the first person to do so.
I'd seen their link on the wiki page that lists sales. But their website doesn't say anything about bitcoins. They were in the same town as me, so I contacted the owner, told him I was interested if I could pick up the gun in person. I got a quote, paid Friday, and just picked up my gun today. Everything went smoothly, the owner was pleasant, all the proper legal paperwork was filled out, etc.
I just wanted to let people know this company is legit, and they will still take bitcoins. They will ship to a local dealer if you don't live in the area.