It's a question many have asked for years, and it's finally been answered!

http://disneyparks.disney.go.com/blog/2010/03/disney-premier-passport-unveiled/

Disney now offers "Disney's Premier Passport," allowing one year of access to all Disney parks in North America (including water parks, DisneyQuest, etc.) and free parking at all resorts for $700. If you think about, that's really a value. A week at Disney World is what, $450, plus $14 a day for parking (which is another hundred). So right there is $550 already.

Plus, the kind of person this is catered to (people who visit Disneyland and Walt Disney World) obviously spend more than a week at each resort.

I think it's a good idea, and I'm sure quite a few people will take advantage of it.

Interestingly:

If you’re already holding a Premium Annual Pass for both Resorts, you’ll automatically be issued a “Disney Premier Passport” – with an expiration date based on the later of the two annual passes.

Lucky for those whose Disneyland pass expires next week and just bought a Disney World pass last week... Though that doesn't necessarily apply to many, I'm sure there are folks in similar situations!

Still, it may be a little pricey for a family of four. But if you have the money, like you said it can be a great deal if you visit both the east and west coast parks.

Haha true... But if it were even $100 less, it would be a short upgrade from a seven-day pass, which wouldn't do much for business unless they had a Disney Airline to connect the two resorts (not included with the pass).

The only down side is many if not most of the resort offers require at least a one day park ticket purchase.

I guess it's a good idea if one were to visit both parks. It would be wise for them to include Extra Magic Hour (it's like KI's DB/Beast ERT) for those passholders, as a bonus for people who won't be visiting both resorts.