If Honda builds a V-8 for a production model in the US, it will be for the RL so they can compete again with the LS430, Q45, and E Class/5 Series.
I doubt they will ever have a AWD setup in a sports car.
It is either rear wheel or front wheel to keep reliability up and maintence expenses down.
I agree with the 3.5 liter V6 powerplant upgrade. Throw the extra cam on as well as the I-VTEC and I'm sure an NSX will give you 330hp +; enough to blow away the Viper and Zo6 on the track.
Rumors I've been stumbling on though is that the next generation Supra will have a V8 and a price of $35k.
That would be nice.