transio: I think the problem is, you're thinking in reverse.
If I were to tell you that I needed an FWD sportscar, would you say that there's no such thing, or to go buy an M100?
If I were to tell you that I needed an SUV based on a semi truck, would you say that there's no such thing, or to go buy an International CXT?
If I were to tell you that I needed a car that could be used as a boat, would you say that there's no such thing, or to go buy a Amphicar (or a Schwimmwagen)?
If I were to tell you that I needed an emergency vehicle that could double as a race car...
See where I'm going? If you can provide an answer for any of those questions, the answer to "do those exist" is yes.
