This weekend, the guys from Idle Thumbs hosted a livestream with Jean Paul LeBreton, formerly of Irrational and 2k Marin, who worked on BioShock 1 and 2 (he's not at Double Fine working on The Cave). He's responsible mainly for Arcadia (he also did a lot of work on the first two levels) in the first game and was lead level designer on the second game.
He played BioShock on the stream while providing insights into the development history of the game (and some brief comments about Bio2 as well). It was highly fascinating and he even showed off his private de-make of Arcadia which he did as a DOOM II map.
I encourage everyone interested in how games are made to check this out or even people who just love BioShock. Hopefully we'll see this kind of dev commentary more often in the future as it provides some insight into development that nobody ever talks about during the typical PR-cycles.
Check out the archived stream (5 parts in total) on their twitch.tv page here: http://www.twitch.tv/idlethumbs