T-Mobile’s forthcoming prepaid data plans have leaked and unfortunately pale in comparison to the best offering in the country in Virgin Mobile’s $40 unlimited mobile broadband plan. The plans consist of $10/100MB for a week of access, $30/300MB or $50 for 1GB over 30 days of access and will be launched later this month with yet another version of the Rocket USB modem bundled with a prepaid SIM, as well as being rolled out to all T-Mobile mobile broadband devices.