some other thingy's you can try:
-canvas size the "line" in system_plugin.rco to x 16 leave y 8
-dummy shadows/glows you don't need
-dummy all images in topmenu_plugin
-try to add as many 8bit iocns as posible,. and add icons with alot of colors as 32bit
-remove the game update,.. and icon,. ;p

If you using big topmenu icons with high resolution's some of these thing will be useless,.. so when you are still loosing icons you have to try and make you topmenu icons smaller,..