So, I spent last night (From the day posted.) making an industrial style staircase to overpass pipes and other structures that can't be moved. I decided to add materials to this one, first by making my own textures, but I ended up using some from NOBIAX @ deviantart.com.
He offers them loosely under a CC-BY lisence, mainly just as free-ware, but I respect his wishes and credit him.
FREE High Quality Game Textures from NOBIAX: NOBIAX @ deviantART.com
Although the poly count is rather high, it is optimised for what it is.
I hope you find a use for it, I separated the floor, pipes, and staircase into vertex groups, so select the stairs and press P, Selection if you need them.
Go visit NOBIAX for free textures and enjoy!
Wow, this is really great.