Everything Apple (the Mac heads thread)

Hyperdrive also do a 2.5" drive case that's compatible, if you've got an existing hdd you could drop in there. Will take up to 1TB.

http://www.hypershop.com/HyperDrive-Hard-Drive-for-iPad-casing-only-p/hdip-000.htm

One on ebay for £94ish: http://www.ebay.co.uk/itm/170696961474

Just looking at Hyperdrive. I have an old ish LaCie HD so no idea if it's 2.5" SATA HDD or not. If not that set up is £155 min.
There's also this which is pricey

I'm wondering if this self powered usb hub would work with the camera connection kit.