"They've put a device together that's targeted toward the U.S. and mature Asian markets," namely Japan and South Korea, plus including several 3G frequencies in all three models for roaming, he said. That may be a smart strategy when it comes to investing in new product versions. "Europe, from an LTE standpoint, has not gained nearly as much momentum as the U.S. and mature Asian markets," Marshall said.

Equipping a phone for many different frequencies -- the CDMA iPhone 5 can be used for 16 different bands, depending on the carrier -- isn't an insurmountable task but presents challenges for makers of chipsets and of subsystems such as amplifiers and filters, as well as the phone vendor, Marshall said. It may even dictate choices about how the phone's motherboard is laid out, allowing for adequate isolation of radio waves from the various bands.

By making more than one model of the iPhone 5, Apple may be reining in the potential costs of that development. Starting with the iPhone 4, it has released separate CDMA and GSM versions, but the fragmentation of different frequencies used for LTE has raised the complexity bar with this release.

"I would anticipate that they will continue to do these multiple [products] rather than try and jam it all into one device," Marshall said. But after several generations of the phone, LTE networks may have matured to the point where there is an obvious set of LTE bands to include in one phone sold around the world, he added.

The many different pieces of spectrum used for LTE is a problem that goes well beyond Apple, and travelers are not expected to be able to on these fast networks in foreign countries for several years.