It has to be said: If Apple releases an iPad with mouse support, what is Steve Jobs going to do about it?
And an iPhone or iPad with Airplay connecting to a TV and wireless mouse and keyboard support with the right software would make a decent desktop computer).
While I in no way question adding mouse support would vastly enhance the iPad (no wonder Android supports mouse via even USB OTG), it's highly improbable it'll ever receive mouse support. "KISS" is their motto.