(I also differ with Qole in pessimism about the possibility of such a network; I see e.g. T-Mobile USA offering unlimited data-only plans at $40/mo, and unlimited quantity data add-ons (for voice plans) at $6/mo (with port-filtering) and $20/mo (w/o filtering); if they achieve decent 3g coverage (which they seemingly plan to) that looks like they're headed there.)