Lets hope that a simple chip with HSDPA for 850/900/1700/1900/2100 support will be available by the time of the N920 (or whatever they call it).

If thats the case then a simple version of the phone will be able to cover the whole globe.

As of LTE/4G is still too early to discuss it.
If you refer to WiMAX that Sprint calls 4G is NOT 4G so it is out of discussion as well.