Na man its speculation.
First, yes the turbo can only spool so much.. what is your alternative? A supercharger? Ok, lets stick a small pulley on the SC to make tons of boost and blow it up before it gets out of the shop.
Second, your acting like there are just big and just small turbos out there. If sized right you can find your medium and it will make more than enough power.
Third, if your not happy with my "second" then you need go ahead and get together with the guys from Porsche and get you a variable speed turbo, so you can have the best of both worlds and be happy. Just a little warning tho, you arent going to come back bragging how cheap it was to us later with this choice.
A supercharger with the right pulley will give you a more linear power curve through a wider range of RPM. This will at very least allow you to somewhat control your torque instead of dumping it all at once at a certain RPM like turbos do. All said and done, no matter what kind of forced injection you run, its going to come back to drivetrain...are you going to just spin through gears making them useless? Will they stand up to the extra power?
Trust me. Going through transmissions every other time you bring your vehicle out is no fun.