I was thinking about this last nite, in regards to newer cars like the F430, Gallardo and even the R8...
Q: What would it take to make another NSX today?
A: Alot more engineering/design than all of the above.
And the reason is because the nature of a supercar includes high maintainence costs and reliability is sacrificed in many of them. For a car to be the next NSX, Honda has to solve these problems while still meeting all the standard design problems of everyone else... Ferrari doesn't have to worry about that.
The only problem with doing something so well the first time is when you have to do it a second time. It's difficult.
I think some people forget how groundbreaking the first NSX was, and for a second car to live up to that heritage of a truely usable everyday exotic will take a tad longer than slapping in a toned down racing engine into a bucket of bolts.