As I see it in the event the WiiHD is true, it will either be a completely new development platform, but not the exclusive development platform for nintendo. That is to say, a "Third Pillar". Or it will be a cosmetic update to the wii ie. hardware scaler, more storage, or any other change that doesn't affect the chipset. Reason being is that nintendo has built a fanatic market with the wii platform, they are still bringing in tons of money with it and creating a new platform would incure more cost on the buyer and thus you get less demand.