How could this be anyone else? Tekkenbob, the official Twitter account for Tekken 6, uploaded this yesterday afternoon, and it looks like Gabe and Tycho are designing a costume for the game.
I suppose the backlit dual-wield weaponry could be argued to be anything - but the Pac Man logo on the gi means it's definitely Cardboard Tube Samurai. Note also the white socks and mandals.
Paustini, a cohost over at Gamertag radio, noticed it too and posits that we should expect to hear more at this year's PAX.
It seems some of website founders Gabe and Tycho's comic genius has made it into Namco's yearly Iron Fist Tournament. Namely, the upcoming Tekken 6, which is heading to Xbox 360 and PS3 this Fall.
If I were you, I'd expect a neat little announcement at this year's Penny Arcade Expo.
Penny Arcade Meets Tekken, Cardboard Tube Samurai a Character in Tekken 6 [Gamertag Radio, thanks mr_raccoon]