I moved from stamping to etching late last year. I built my own electro etcher. It cuts on DC and darkens on AC like the Personalizer. Many of the guys over at BF and elsewhere have done the same, there is a good set of easy to follow directions and a parts list for the build at this page:
http://chriscrawfordknives.com/electro-etching-unit/4535265119
All of the electronic parts can be ordered online from Radio Shack, the parts list has the RS part numbers and all. My out-of pocket for the whole build was about $65. It took me probably three hours to build, and the result is a very good marking machine. Many who have built the machine have added a 12V/24V selector switch so that one may choose how aggressively the machine cuts. Others have used an 18V transformer instead of the 12V, and arrived at the current they wanted. Searching in shoptalk at BF will yield good explanations of these mods.
I use mine as the original plans show, at 12V. It works fine.
Then I went and ordered stencils from Ernie Grospitch, who is great to work with. He was very helpful with mark design and sizing, and I think he shipped the stencils before I even payed him. They got here fast and work great, you may burn a couple while learning but after that they are very durable and one will make MANY marks.
http://www.erniesknives.com/knifemaker_stencil.html
Just my $0.02.