If you're not looking to temper the chocolate - simply melt it, then two stock pots will easily do what you need. I've melted thousands of pounds of cocoa butter this way.
One large stock pot holds the water, and the other (slightly smaller) sits in it with the water going up the side of the smaller one about 6 inches.
This is simply the layman's version of a $8,000 water jacketed Savage Melter.
You don't even need the expensive kind of stock pots. Jut make sure they are stainless steel. I think mine cost me about $50 each 7 years ago.
No need to buy a fancy machine if you are just melting chocolate.
Brad
updated by @brad-churchill: 08/26/15 16:07:04