The Nexus 4 is out, it's cheap, and it's unlocked. Those two features combined for a quick sell out and unfortunately, a bunch of headaches for customers. What's clear though, is that there is a demand for the Nexus which offers quick updates and a vanilla version of Android that can't be found on other smartphones.
With the Nexus 5, Google may opt for a return to 4G LTE, something that the masses wanted from the Nexus 4 but did not get. With Galaxy Nexus owners coming off-contract, the timing may be right.
Release Date: Unknown, likely in late 2013.