There have been several conversions with several different approaches of varrying levels of success. Do some searching and read through the threads. I know that some of the guys who converted them have come back on thier build threads and and updated them as the parts failed and had to be re-engineered. Reading through these threads could save you a lot of trial and error cost. Small haul's build thread comes to mind where he wrote about the various ways he perfected his design.
http://www.rctruckandconstruction.co...ght=small+haul
It looks to be a very functional conversion in his videos posted on youtube.
http://www.youtube.com/watch?v=UtWexO8xheM