Background:

I use marking menus a lot when working in Maya, but when changing versions or machines udpating the marking menus is always problematic. While looking for a way to allow me to tranfere my settings I found 
contextToolsMM.mel

     69: // allow user to define a proc with additional menu items
     70: if (`exists contextPolyToolsDefaultUserMM`)
     71:          contextPolyToolsDefaultUserMM $parent;
     72: return;

Description:

So here is my plugin which adds 5 marking menu files to your Maya,
     1. menu_contextPolyToolsDefaultUserMM.mel
     2. menu_contextPolyToolsObjectUserMM.mel
     3. menu_contextPolyToolsVertexUserMM.mel
     4. menu_contextPolyToolsEdgeUserMM.mel
     5. menu_contextPolyToolsFaceUserMM.mel
Plus it creates the necessary functions which links into the existing context sensitive marking menus (Default, Object, Vertex, Edge & Face).

Install:
     1. Place file in your C:/Program Files/Autodesk/Maya2012/bin/plug-ins folder, or similar
     2. Load Maya
     3. Activate Plug-in via Window->Settings/Preferences/Plug-in Manager
     4. Open Window->Settings/Preferences/Marking Menu Editor
     5. Customise menus as normal