You're right Ross, I'd definately want to cut my teeth on easier jobs, patch repairs etc, leave the heavier stuff to someone more experienced especially where safety is concerned.
I know you've looked into it too... in fact the saloon probably is the best base to build from.
I did at one point think of 5-doors, using the rearmost section of roof and bootlid to form the back window (With spoiler) but the bootlid actually covers way more space than I thought, the load bay would end up being smaller than the 3 door version! And pickups with backwards slanting doors look strange.
I'm sure there is a way to do it that looks good, is safe, and offers most loadbed for buck.