E911 additives

More discussion on this regulatory problem here. This problem seems to me to be based around somewhat old technology. We seem to be addressing it assuming that the infrastructure must operate the way it does now.
What does an E911 service have to do? It must allow you to communicate with the relevant authority, it must allow them to determine your place of calling, and it should be reliable; specifically not dependant on your credit with your communications provider.
Clearly, the ability to communicate with the authorities is not diminished by IP based tools, only enhanced, for example by messaging and presence. It would be simple enough to configure and route a specific number (e.g. 911) to the current fixed line providers too.
The issue comes in detemining location, especially in the expanding wireless internet arena. For example, with Wimax, how will the location of a node be determined and reported?
Personally I would favour the introduction of GPS into all mobile communications hardware (laptops, pdas). It might add something to the cost of the hardware (about $129 currently for an add-on for PDA), but the cost would come down rapidly because of the volume, and the benefits would go far beyond the E911 capabilities.
This hardware can then be E911 certified and the guidelines would be that a communications provider must verify (through SNMP-like approach) that the equipment connected (at the time of intial connection!) is certified hardware. If you don't know what I'm talking about and want to know more, Skype me!

In this way, in order for a service such as Skype to be sold (note emphasis) to you, Skype would have to verify the GPS location through some standard protocol (but you could always use your mate's phone for sign-up).
If you use a non-certified phone, then you don't get E911 service.