Keep looking on craigslist for your area. You can also check the classified section of HBT to see if there's anything that makes sense to you...
Personally, I just picked up a 32qt aluminum stock pot from a restaurant supplier and installed a ball valve on my own when I was ready.
If you're patient, and don't want to make the kettle yourself, start searching. You should also look through the vendors listed in the section to see if any have specials going on. Maybe even contact some to see if they have any 'scratch and dent' kettles that you can get at a discount.