Corney Cooler build advice needed

So a friend and I have decided to build a 3 keg cooler out of an old rain barrel for parties. I decided that I wanted to put draft taps on this cooler instead of picnic taps since I have spare taps from a misc lot I purchased about a year ago. My question is what size shank should I get for this since I am not familiar with setting up a draft tap? I thought about buying an elbow shank so the lines turn away from the kegs some but wanted to get the opinion of the forum. The wall of the barrel is about 1/4" thick. Is there anything else that I would need to purchase other than maybe this?

http://www.amazon.com/dp/B004S5BA1Q/?tag=skimlinks_replacement-20


Or would I be better to just purchase a straight shank

Any help or guidance would be appreciated.

Thanks

This is an interesting idea, but I am having trouble picturing the setup. What is the rain barrel exactly? Is it one of those 55gal heavy plastic drums? Would the CO2 tank fit inside also? I think the shank you showed would work fine if I am picturing it correctly. Also, is the wall rigid enough that it won't flex terribly when pulling on the tap?

It is a 55 gallon plastic drum. I will post pictures of the process as much as I can upon completion. The walls are pretty stiff so I am not too terribly worried about flexing and I plan on fabricating a drip pan/shelf for the taps so that will only add to the stability. Would that shank be the only thing that I need other than the faucet itself? The CO2 tank could easily fit into the barrel from what I am seeing after cutting the barrel open so it will be a nice completely self-contained party/picnic setup.