|Behold my fantastic 3D skillz...|
Since the official install instructions were a bit lacking for linux I thought I should write up how I got it working on Ubuntu Mate 14.10. First of all, unlike OS X and Windows, there's no install file on linux. I suggest reading through the Chaos Group instructions anyway since I'll skip the obvious parts here.
Start by installing V-Ray 3 standalone. Download the latest Blender (I used v2.73a) and the appropriate V-Ray plugin.
Unpack the Blender files wherever you like, I just kept everything on my desktop since this was just a test. You then need to extract the V-Ray plugin to it's own directory. Don't worry this will only be temporary since the next step is to copy all files (including the custom blender binary) into the blender folders you created in the first step.
A drag and drop copy didn't work for me and I ended up using the rsync command in terminal to get it to work properly like this:
rsync -rav ./vray_plugin_directory/ ./blender_program_directory/
Obviously you should change the directory names in this example.
That's it. Now you should be able to fire up Blender by using the new binary file.