I have had this site in my faves/bookmarks for about a year now and finally joinede and had a lot of inspiration looking through the different builds and reading a lot about the build of TD's.. Here is the chassis I will be building on.

The wheel arches removed

The 'A' frame

The size of the bed is 81" x 50" (outside to outside). It has 10" wheels. The centre of the wheel is 36" from the end of the chassis.
I recon a 8 x 4 will fit on here perfectly.
I hope. lol
Thanks. Ian