Any idea how I could fabricate one to look similar?
You can get the majority of it by:
1. determine how wide you want the fender to be.
2. buy a standard fender that width.
3. cut about the third you need off of the back end. Lay your existing fender on to mark off your line so that you can cut the ears into the fender.
4. the rest is fiberglass work. find a spacer to fit between your tire and the piece of fender you cut out to set the proper angle. Then install the covered seat where it belongs. Finally lay the fiberglass over the seat in the shape of your choosing.
5. once the fiberglass sets, pull the seat out of the way and clean/finish the shaping with body putty.
6. paint, install and admire.
That looks to be mounted without a grab bar, and using a corbin saddle. If they showed a top view, I expect something was done to create a fuel door. The fender looks to be supported by the same bolt holes the Corbin fixes to, so these points and the tabs you cut into the front side of the fender should support it just fine.