I had the idea to build a 59 extended cab about 10 years before I actually did it, so I spent a lot of time thinking about how to make it easy...and using a donor suburban body definitely did make it easy.
One problem with a short extension is that the quarter window looks too small, the pillar between the door glass and quarter glasss is almost as wide as the quarter glass. A longer extension looks more natural.
Shortening the frame is much easier than lengthening the cab, too....
