What I really want is for a high-speed, wide area data network like Wimax to spread across the world, and for the tablets to get a radio for it. This would give me access to all of the current VoIP / IM / e-mail / whatever, everywhere.

Nokia has already demonstrated willingness to step up to the plate (with their N810W), but there's very little incentive for current phone companies to build out such a network because they'd be slaughtering their restrictive, proprietary cash cows (you guys have heard about the 15c per text message in Canada, eh?) for a dangerously open and unrestricted network. I would actually say that there's a disincentive for telcos to do it. I get the feeling that telcos only offered high speed internet (DSL) when the cable companies started offering it. I think the only hope of such a network blossoming is if a group of electric companies banded together, put antennas on power line poles everywhere, and started offering something like Wimax. That would force the entrenched companies to compete.