If Sprint worked out roaming deals with these international LTE companies in supported bands, then a change of SIM is unnecessary. However, for international LTE use with a non roaming partner within a supported band would require a purchase of a local SIM. However, as pointed out above, since Sprint has sealed SIMs, this won't be possible.
I think Sprint will get to the point of LTE international roaming with partners that use the same bands in the next 12 months.
Robert via Kindle Fire using Forum Runner