If You Can Build a Car of Your own, What do you want?

Simple as that. I got the idea from my friend who work at a coachbuilder company as a bus designer, and he said he can build a car for me as long as i got my own design and chassis and drivetrain and money.

I think i'll want something rather realistic, i want a W140 chassis with a front mounted Mercedes V12 but in a some sort of grand tourer coach-built body like that Maserati, altough i'll want my own design. It should be badass.