Hi Gav, unfortunately the tools that I use for constructing the MoI Mac version do not currently have any mechanism in them to handle the Retina display so at the moment there's not really much that I can do about it.

It may take a while for the XQuartz environment to get updated to enable full Retina support.

If you set your screen to the actual full 2880x1800 resolution then it should work, although a lot of stuff will probably have tiny text there. You need to use a separate utility to switch to the actual full resolution since Apple hides it in the regular controls. Here's one utility for that:
http://wineskin.urgesoftware.com/tiki-view_blog_post.php?postId=51


There are a lot of programs and also development tools that need to be adjusted for the new Retina screen behavior and it may take a while for all the various tools to get updated and for the updates to trickle down to the particular system that MoI uses.

- Michael