EDIT: TESTED 14/11/2012 after recent patch on PC - Still works :) As per requested, This is a simple tutorial on how to farm Captain Blade's lost treasure room in Borderlands 2 DLC Captain Scarlett and her Pirate's Booty.
It can be tricky to begin with but when you understand how it works and where you need to jump / crouch it will get easier.
I added an overlay explaining that sometimes when you start jumping and crouching in that area the glitch may happen at any time, If it does happen try to stay still and only press jump - If you constantly gain height ( elevator ) you have done it correctly.
The best way to do it is from the invisible corner, but sometimes you can actually fall through the floor - So be aware that the glitch sometimes won't work and you will have to reload your game.
Shout outs to whoever first discovered this path to access the treasure cave, I have seen a few videos But I am unsure who actually was the first, I tip my hat to you good sir / Madam.
Edit: - It appears that http://www.youtube.com/user/imapuncha Was the first one to find / record this method - Props to him for using his brain to figure this one out.