It would seem that the Borderlands phenomenon is coming to iOS devices shortly as members at the Gearbox forum, have unearthed an advertisment for a game called Borderlands Legends in the digital strategy guide.
According to the ad, you will play as Mordecai, Lilith, Roland and Brick, characters from the first game, and there will be lots of weapons to collect (as you'd suspect). With this being the first we've heard of the game the October release sounds optimistic, but it's iOS so you never know.