I seem to think that 10 day passes are available for purchase in the UK only. I'm sure someone will correct me if I'm wrong!
However, as the exchange rate is so good, why not consider buying a Fun in the Sun pass which you would pay for in dollars? They allow unlimited access for 30 consecutive days to all Disney parks, water parks, Kennedy Space Centre and some other places and include a character breakfast!
They are not widely advertised but you can get them from Paramount (someone else on the boards may be able to post the website or the email address for a lady called Rosa who works there - very helpful she is too!). Ticketmania also do them, but are supposed to only be available to subscribers to Mousesavers.com. I happen to be a subscriber and could let you have the website if you PM me.
Current tickets are $300 each for adults, and $245 for kids - so they work out very cheap at the current exchange rates. Paramount charge extra for p&p, but Ticketmania don't.
The only downside is that the tickets currently on sale expire at the end of May - but new ones with a later expiry date may be available soon.
Julie