What do you think about the Powerslot Plus sized rotor systems? Last I checked, they offer front and rear rotors kits for the 5th gen that just simply relocate the factory calipers to accomdate the larger rotors.
This should, as you stated, improve the leverage of the calipers and improve the heat capacity of the Prelude brake system, both good things obviously. I would think that if you did the larger rotors for the front AND rear at the same time, bias should remain good, with no drawbacks and all positives. However, for the 4th gen Prelude they ONLY offer a larger front rotor and nothing for the rear. I've toyed around with the idea of getting the larger rotors for my 4th gen VTEC, but never pulled the trigger due to my concern that it might shift the bias even further forward.
More info here:
http://www.powerslot.com/pages/power_slot_plus.php
Let me know what you think.
Gracias

,
Mike