^^^ ive never even heard of camburg. learn new things on this forum everytime I visit
op, you need to do a search on here. theres lots of info to be found on this site regarding most every conversion available. plus some of those places are people on this forum and have proven to be very helpful members of this little online society.
also keep in mind your location. I see lots of good things about advanced from people who live in that area, but most everyone who doenst and has had work done by the seems to have a bad taste in their mouth from the experience. just calling them left one in my mouth...
and, just a couple i see left off of carringb's list. derek at colorado campervans does 4x4 conversions for the econolines and theres also a small fabshop in idaho falls idaho that will also convert your van. again, location would play a big part for me personally.
and just an fyi, the people who converted my van paid quigley 14k to do the conversion in 2003.