I just sent him an email to make sure it's ok and see if he knows of anyplace in your area that might be a good source for you. Figured he might be able to locate a recycle center/service that gets kegs out there that you could buy from (as a plan A)...
For the polishing method, I do a modified version of what Bobby_M posted up. I got the Gator finishing pads, and backing pad, for my 4.5" right angel grinder. On my first one I started with the course and then used the medium pad. I couldn't locate the fine pads at that time. I then went to the polishing pads with different compound sticks. Took me about 8 hours to get the keggle to where I was ok with it. The one I'm going to convert next (selling my first one) I only needed to use the fine pads, and then only one package of them. I then started polishing it up starting with the ebony compound and going through different ones until it had a nice shine/polish to it. I got the compound sticks from Amazon. Just get ones that are made for working on stainless steel and you'll be fine. Plan on using a couple of pads (or more) per compound to get the polish there. I would also get ear plugs (good ones) and a breather mask (or several of them). Safety glasses are a good idea if you don't wear glasses already (and maybe even then). If you have access to an actual polisher, I would use that as a final stage to put a real high gloss on it. If you have a variable speed grinder, that would be great too. That way you can run it at a lower speed one last time to get anything left behind. You can also get buffing wheels, provided the hole works with your grinder. I have a few of those, but I lost the backing disc for the grinder I've been using. I'm hesitant to use my other grinder for this, since I don't want to gunk it all up. If I cannot locate the disc soon, I might anyway.