From a quick scout about it appears that unity isn't modular at present, so you can't have the globalmenu without unity.

But you can effectively remove the unity dock from your desktop.

Install CCSM apt-get install compizconfig-settings-manager

Under the Ubuntu Unity Plugin section make the following changes:

• Reveal Mode: Change this so that none of the edges are selected


• Set Hide Launcher to 'Auto-hide'


• Clear the short-cut keys

That will make the unity dock disappear immediately after launching.

You can then get your gnome-panels back by adding 'gnome-panel' to your start-up applications using the control centre.