There's an ad in April's kiwirider, page 88.
Offer includes flights, transfers for all days, accom in houses on PI, grandstand seats, insurance and taxes.
No price listed, but email to

motogp@trackfun.co.nz

Let me know how you get on.

Oh, and I know you're not after a piss up, but they state "entertainment kiwirider style". Should at least have access to a bar. Us, we're on it in the van in the campsite.