This is not a custom figure, but a custom car. I took two broken Ecto-1 cars(one had a broken hood, the other had a broken body frame) and combined them together. I cut the top out and used model filler to smooth it over a square piece of vinyl, which took HOURS to get right. Days actually.
The gadgets on the roof were from various scrap and parts from an Ecto-1 model kit. I also smoothed over the doors and a few other things. The flashing lights are from some Gi Joe knockoff police rescue set. The whole toy is repainted and it took several revisions before I was happy with the results.
I intend for it to scale with my Mattel figures. They can't fit because of their proton packs, but they scale with it pretty well.