I have just tried to install mint-x on my ubuntu 12.10 OS from different sources and unfortunately I got this:
It works perfectly, but the GTK+ theme part fails to reproduce the same theme that linux mint is using. The window and icon themes work perfectly, but the gtk+ theme doesnt. Any ideas why? I have used this source to get the latest gtk+ theme for mint-X: http://packages.linuxmint.com/pool/main/m/mint-x-theme/
SOLVED: after I ran the update manager....that triggered some changes in the gtk and now it looks just fine.