The CyanogenMod team has started rolling out CM10.1 nightlies for the Nexus 4 a.k.a Mako. The CyanogenMod team noticed that quite a few ‘developers’ had kanged the mako device tree from their git, and released kanged versions of CM10.1 for the Nexus 4, which was surprisingly being used by many people. Thus, the team decided to release official nightly builds for the handset.
Keep in mind that the CyanogenMod team still has not synced Android 4.2.1 to their repos, so the current CM10.1 builds are based on Android 4.2. However, knowing the CM team, it should be a matter of just a couple of new nightlies before Android 4.2.1 is integrated into the CM sources.