very interesting idea and I'm sure some of us could find some use around the vanagon

http://www.davidbradley.net/ERR.html

Quote from site

Background:
At a recent consignment sale held in south-central Pennsylvania, a Bradley collector (known to some as 'SPB') was leaving with his well rusted treasures. As he was making the 300 yard trek to his vehicle, a fellow collector shouted out "why don't you try electrolytic rust removal". SPB grunted and went on his way, but later, the possibilities of electrolytic rust removal (ERR from this point forward) were discussed. This report is the result of several hours of playing with rusted Bradley parts in my driveway (my neighbors are really patient people).
Conclusion:
I was impressed! I've used Naval Jelly for years. That's caustic, smelly, expensive, and doesn't do nearly as good a job. This process is easily scaled up for doing bigger jobs. I'd like to get a cast iron kettle, or better yet, an old cast iron bath tub with the enamel removed (my neighbors are really smiling now!). Ideally, the electrode should be stainless steel. Supposedly stainless is not consumed by the process like the butter cookie can was. Finally, the ability to do large parts, makes this process competitive with sand blasting. As for total rust removal, (I can see Dave Phelps frowning) painting and time will tell. I was pretty satisfied with the sample I did, but rust is insidious, and it usually wins.
Thank you for visiting my Electrolytic Rust Removal Page!
and linked from his site a larger scale.   derusting a trailer frame http://www.oldengine.org/members/billd/trailer-electrolysis.htm