There has been core work done in this area since 3.9. There is a domain mapping plugin available that makes use of this, called “Mercator”, though it’s not yet at the full capability of *this* plugin.
This version will work, but as stated before: for best compatibility, do not use this, get the very latest trunk version. It appears the developer is not ready to release it here, so you’ll have to go find it in the repository (link?). There’s also a link to a patched version in the tutorial, which is linked from the read me file.