I successfully installed ubuntu touch on my Nexus 4 yesterday alongside cyanogenmod 10.2. Today I used the method described on the ubuntu wiki to install the "Ubuntu Dual Boot Installer" on my Nexus 5 alongside cyanogenmod 11, but the app doesn't have the "Trusty" channel available like it did yesterday. It just says "Install Ubuntu--no channels available".
This forum post recommend changing my /system/build.prop file to have these values:
- ro.product.model=Nexus 4
But I'm afraid of what that will do to my android installation.