The most common way to build a Willys is probably as a gasser or street machine. I've seen a couple of customs, but they're rare. I think one reason is that the Willys is quite small for a custom car, especially if you've chopped the top on it.
I wanted to create a 1941 Willys custom but stretch the measurements more closely toward those of a '36 Ford three-window. This makes the project a real dream car for most of us. Surgery is really difficult to do for this kind of body and almost all the surfaces have to be reworked; it's like stretching an egg shell. I created an outline picture to help visualize where and how much it's modified.
On the other hand we have seen some aluminum Willys bodies done by very skilled sheetmetal men. This requires a little more than that, but it's not impossible. There are plenty of 'glass bodies for sculptors-they're even made in Scandinavia.
The front sheetmetal is extended to make it possible to create a straight door. The door is only a little bit longer than the original. The top is chopped about 4 inches, giving the windshield stainless trim. The whole car is lengthened a couple of inches in the middle of the door. Running boards are heavily restyled and molded; original ones are smaller and very square. The rear fenders are also molded to the body and have flush skirts.
The grille and headlights are stock, retaining the typical look for the Willys. Bumpers are '41 Ford items and may need some reshaping to fit properly. The rear view is not shown, but I was thinking of using '46-48 Ford bumper guards with lucite lights on them. Hubcaps are handmade with some simple Art Deco styling and maybe a cool emblem in the center. Tires would be 6.70-15 bias-ply whitewalls. All the trim is shaved, but original side trim would work really well with this concept. The stance is pure tail dragger, not slammed to the ground but driveable and good looking at its lowest point.