i'd love to see hamachi on the ipad. there's really no reason why it couldn't work though... Juniper offer's their ssl VPN product that works essentially the same way
Cisco Anyconnect does this. It puts a VPN in the VPN list that I don't think is any of the three default VPN types in the iPad. Or, how come Hamachi can't set up a proxy in iOS that forwards certain connections to the Hamachi servers?