There are several vendors who offer quality parts that you can build a form 1 can with. You can find tubes and other parts machined from titanium, stainless steel, and aluminum. These require some finishing work by the builder.
You can spend as much on these parts as buying a commercial can, or close to it. The biggest advantage to going this route right now is that ATF is approving form 1 submissions in as little as 30 days.
I recommend that anyone interested in doing this take a look at Form1suppresor.boards.net. There is a wealth of information available there.