UPDATE:
I found the old soft sided cooler that i was looking for. Although it is a tight fit, it does fit.
The problem is the cooler is not exactly leak proof.
After about 10 minutes it went from tap water to freezing cold icy water, yummy...
Now i gotta figure out how to get that cooler water tight. The lining in it looks pretty rugged and like it would be water tight, but sadly its not. Any ideas? All i can think of is to get some sort of heavy duty rubber bladder to fit to the inside of it. Anyone know where to find something like this or have any better ideas?