Sid,
Might be worth having a chat with Jasper or Stu from the Kamikazees - they've got a site at Carlisle, unless that was the site you were thinking of anyway... They've just moved to a new location with access for Woodland and Sup'air. I don't know how much room they have for Sup'air though so don't know how many fields they could cope with.
I second Si - the Hellfish would be interested, though there *must* be more teams who'd want to come, who'd find this event convenient. Stormbirds? 6e Marshalls? Kamikazees?