Has anyone thought of using one of these?
http://www.trailerpartsdepot.com/itemdesc.asp?ic=HPB3530101&eq=HPB3530101A&Tp=
http://www.trailerpartsdepot.com/itemdesc.asp?ic=HPB3530101&eq=HPB3530101A&Tp=
IMHO it's more solid and cheaper to fab in something like Geotracker90 did on The Gillz Expo Off-Road Trailer. A slide in-out adjustable.