Race-Taxi is a Swiss project that shows what a few guys with a garage, three donor cars, and lots of spare time and disposable income can do.
Step 1: Find a donor van. Bonus points if it's a split window. (1962 model here.)
2. Find a donor Porsche engine. In this case, it's from a totaled 993 Turbo. Increase horsepower from 408 to over 500.
3. Find a chassis donor, in this case a Type 2 (T3), or Vanagon here in the States.
4. Remove the body from the chassis.
5. Widen and lengthen the bus by sawing it into quarters. Mate the body to the Porsche engine and T3 chassis.
6. Add a whole bunch of wires, Recaro seats, the Porsche's gauges, and a nifty wooden shift knob.
7. Lots of body work and paint.
8. Almost done.
9. Take it to the track and blow the doors off of Imprezas, Elises, and old M3s.