Yes, monster watt hungry PCI Express cards is coming as we already know. A specification for PCI Express 225W/300W cards are in the pipeline:
http://www.pcisig.com/specifications/pciexpress/review_zone#gce
This specification is a PCI Express 225W/300W Card Electromechanical document that addresses graphics power and thermals greater than those supported by PCI Express CEM 1.1 and PCI Express 150W 1.0.
http://www.pcisig.com/specifications/pciexpress/review_zone#gce