PCS repeaters already available
While Netgear's concept is a much better approach in that it integrates the 3G with wireline and 802.11 wireless, there are already "microcell" repeaters in the 1.2GHz (I think...above 900 MHz...) band for rebroadcasting your up and down link from a PCS cell phone or EVDO modem. I currently use one to improve coverage inside our RVs when we're camped at the edge of a MMA (the usual spot to find campgrounds) and need the extra "punch" to get out. I don't think the power is that great, but a 3dB external antenna makes a BIG difference...
BTW, the repeaters are on sale without license from major electronics resellers here in the U.S.