World traveler Kym Bolton now sells replacement wheels for Canter and Isuzu models. Kym used wheels like these on his recent journey across Alaska and western Canada in an EarthCruiser camper. The web page has good suggestions about tyres to use with the wheels.
http://www.goannatracks.com/Home/Super_Single_Rims_for_Canter_&_Isuzu.html
http://www.goannatracks.com/Home/Super_Single_Rims_for_Canter_&_Isuzu.html