This makes zero sense.The name iPad isn't simiar to iPod, the iPad is replacing the iPod.
They will be two separate product lines. iPod is an established line of pocketable multimedia devices, the market leader. iPad would represent a brand-new non-pocketable tablet.
Changing iPod to iPad would be confusing to the marketplace and adds zero marketing benefit to a highly recognizable trademark. It would be like Apple arbitrarily changing their computer line from Mac to Mick.