I have been thinking about this aprticular issue for quite some time. The ideal solution would address both sides of the guest management: authorization for guests to get access and provisioning of the temporary account on the wireless infrastructure.
To have access to our facility, guests must be pre-registered in the security system. At time of registration, I want to be able to check-in that guest is to be provided wireless access. This should trigger the required provisioning of user login and password in the wireless infrastructure for the time duration of the visit (hours, days, weeks). When the guest shows up at the reception, his temporary badge is published together with the login details for wireless.
So the ideal solution would integrate with any guest registration system on one side and any wireless user account provisioning on the other.
Alain