SIM card slot on models equiped with 3G/UMTS/GPS
Modem is undecided yet, it is speculated that it will be a PLS-8-E 
GSM/LTE is most prevalent, and would mean only one chip in all pyras. For reference these are the networks and frequencies used in Europe and The US Another variable is price. A 3g modem is cheaper than a 4g one. But they are pin-compatible, which means a decision can be made based on demand. It is also possible to upgrade to 4G by moving to those in production at a later stage.
All models will be available for preorders and will be produced based on those orders.