Sailfish OS 1.1.1.27 alpha 5 for Nexus 5 (hammerhead) was released in January 14th 2015 :
Adaptations/libhybris/Install SailfishOS for hammerhead
[ROM] [14Jan] [GNU/Linux] Sailfish OS (Alpha) - now with MultiROM

Known issues :
- OTA Updates do not work;
- the camera does not work;
- Android app support is not available.

Changelog:
* 2014-11-27 MultirROM users: if your primary ROM is Lollipop based, just install any SailfishOS version accompanied with CM11 .zip, and you'll have best of both worlds working! Thanks to @julle131 for finding this!
* Alpha5 - 14 January 2015
- WLAN remembers last connected AP after reboot - bug fixed
- Sailfish OS Update 10
- Fingerterm app scaled to the screen size
- Help us close this bug down - I could not reproduce it during 1st bootup
* Alpha4 - 18 December :
- Jolla Store enabled (but do not add Jolla Account during start-up wizard, skip and then add later, due to a known issue);
- Sailfish OS Update 9;
- Magnetometer support;
- Improved BT HID support (US bt keyboard layout provided);
- Generic BT improvements;