Postpaid-Equivalent Prepaid MVNOs?

[Fixx42]

Hello all,

Does anyone know of GSM MVNOs with coverage areas roughly equivalent to those available to post-paid customers (i.e. significant capability to roam onto other networks), besides Tracfone/Net10/Straight Talk?

Many thanks!
Fixx

[HF305]

Truphone uses both AT&T and T-Mobile. Unless you're interested in regional carriers, there isn't much advantage to GSM roaming between the big two in the USA-- practically everywhere T-Mobile covers is duplicated by AT&T.