Restaurant supply stores do vary in their policies. Some will only deal with corporate accounts but many will sell to anyone. Luckily the ones near my house will sell to the public. I do have one on the way from Amazon.com but it's not gonna be as heavy duty as a high-end pot like a Vollrath. The best ones are 22 gauge, whereas the thinner ones actually are 8/18. Good to know about the aluminum-dementia thing being myth. Still, aluminum is a terrible thing to cook in. First, it's reactive and pits badly. Unless it's hard anodized you really can't use it for anything acidic, and even tomatos are rough on it. It heats unevenly, too.
Again, for a full on cookset, I recommend a cook set.
But if you want something primarily to boil water it would rock to have a tall pot with a lid, large enough to hold a full 1 liter Nalgene.
I'll see how the one works from Amazon.com, and if it's not quite the right size or too flimsy I'll check out my local suppliers.