No matter what way it is built, there will always be custom parts somewhere, but there are many OEM hubs etc that could be utilised which would keep costs down.

Ultimately layout, suspension design outside of this as well as geometry will all factor into how it handles far above any individual OEM parts used.

The front engine, rear transaxle would certainly be another option and probably give a very nice safe weight balance...but it would also heavily eat into passenger space in the cabin.

The mid engine, transverse, ie fwd layout would be by far the easiest as the entire drivetrain is a single package that just needs moved.