There have been rumors that Google may be introducing the Nexus 5 at a slightly higher price point (although Google Play's "accidental" posting don't support the idea), and adding in an official LTE variant of the Nexus 4 as the low-end model in the lineup. There hadn't been much proof to support the idea, but a new filing at the Bluetooth SIG seems to confirm an LTE Nexus 4 on the way...
Source: http://www.phonearena.com/news/Probable-LTE-Nexus-4-passes-through-Bluetooth-SIG_id48724
Source: http://www.phonearena.com/news/Probable-LTE-Nexus-4-passes-through-Bluetooth-SIG_id48724