The article has some pretty good details, and while speculative, second sourcing LTE modems would make a lot of sense, no? The comments seem to be missing the SIP[0] aspect of modern electronic device manufacturing which Apple and others are pursuing[1]... it allows for some "strange bedfellows" and would explain a joint TSMC / Intel solution.
[0] https://en.wikipedia.org/wiki/System_in_package [1] http://www.wsj.com/articles/hon-hai-loses-battle-to-control-...