Reply to post:

In the past I've tried a 'headless' esxi 5.1 on a mac mini (intel gpu gfx) with a virtualised linux, windows + osx vm (with gpu passed through it it) as it would appear to be the best solution but never got it to work properly :( esxi 5.5 appears to have the same issues I had which is a shame:-

https://communities.vmware.com/message/2330282

So instead I'd recommend Xen & Debian Stable would seem to be the way to go:-

http://linux-bsd-sharing.blogspot.co.uk/2012/10/howto-xen-413-windows-8-hvm-domu-with.html