I may have just purchased the same cooler from walmart, and I used basically the same hardware in that you'll see in this thread about converting a 10 Gallon Rubbermaid. I used a CPVC Manifold instead of a braid though.
With the manifold, even when the level of the wort is below the drain spigot, you have a siphon effect going, so it doesn't actually stop until it hits the bottom of the manifold. On mine, the wall for the drain port is actually angled up, so I had to use a 45 degree fitting to make it level, then a 90 degree fitting to get to the manifold.
As for using it as a cooler, I think my 1/2 ball valve doesn't actually hit the ground, but I'm not 100% sure. The cooler was only like $30, and I'm getting a heck of a lot of use out of it as a homebrew equipment storage device, and considering the amount of time it took to get everything working, I would just as soon buy a second cooler before I use this one as a cooler. But that's my opinion :-)
BTW, I think you probably should post this kind of question in DIY Projects.