If we could get even just ONE new Mac mini, it would be neat.
I really believe that Apple will use just one platform for it and I don't believe that the nvidia 9400m is that much more expensive than a X3100/X4500 one. The price increase on the new MB is probably due to the unibody enclosure (irrelevent for the Mac mini) and the LED-BL display (irrelevant as well).
I believe they can update the Mac mini to the new MB specs for the current prices (but that could mean without firewire...)
$599, 2.00GHz, 2GB RAM, 160GB HDD, Superdrive, 9400m IGP
$799, 2.40GHz, 2GB RAM, 250GB HDD, Superdrive, 9400m IGP
and they probably could go all the way to:
$999, 2.53GHz, 2GB RAM, 320GB HDD, Superdrive, 9400m IGP
if they wanted to (and depending on what will be the specs of the next iMacs).