Can the iPad have multiple users?
Apple really designed the iPad as a 1-to-1 device (one device to one person) so I don't think there is an EASY way.

I know they have deployment products out there that might make it so you can remove and restore profiles, but it's not on the fly and I think it's very clunky.

I also did a quick Google and noticed this software that is out in beta and is exactly what you want, but it looks quite experimental and your iPad needs to be jailbroken to install it: http://nowsci.com/userprofiles/