We bought a wagon without a cut through cab and sent it to a local mechanical engineering garage to be converted . My OH is a highly skilled diesel fitter / mechanic and whilst he was happy to take on most jobs that required doing on our wagon ( installing water tanks , replacing the ramp etc ) this is one job that he absolutely would not do himself . It is a highly skilled job because once you start altering the infra structure of the vehicle the whole thing can become dangerously unstable - a bit like removing a supporting wall in a house and knowing how to put in a RSJ ! Our project was made a bit more complicated by the fact that we wanted to retain the tilt cab but they did an excellent job . To the best of my memory it cost around £650 - and that was about 12 years ago ( it's a much bigger job than most people think !).