Haha, thanks man! I don't work for them, unfortunately. Now to be honest, I would love to, I love their weapon design and whole "1 billion weapons" ingame generator.
I really wanted to try something new an unique for my portfolio, I did couple TF2 weapons and I also do realistic texturing a lot. Borderlands has very specific texturing style, different from TF2, I really wanted to make it as close to that style as possible. It's good to have couple different pieces in portfolio, show that artist can adapt to various visual styles.