There's a thread for this on the RAZR Android Development forum, and unfortunately the developer is too busy to work on it right now.
The last working Ubuntu Touch image we have dates back to last March, at which point it was not in a generally usable state. I have tried following the documented build process myself with a more recent version of Ubuntu Touch, without success. (See earlier in that thread.) Building for XT910 is a tricky process due to our phones' signed bootloader, and thus having to kexec a more modern kernel.
For the moment it seems we're out of luck!