Despair not, I found a pretty neat way to achieve my goal.

I just have a little mini-tray as well as the systray. Using systray2 for the main system tray, and I keep it hidden most of the time. Using VTray for the mini-tray as it supports scrolling. I have the mini-tray always visible and it just displays 2 icons: 1 is a built-in shortcut that reports when you have new e-mail, the other is any system try icon. There are 2 buttons you can use that scroll the mini-tray so you can select exactly which systray icon you want to display.

That means people can have whatever systray icon they want showing as their mini-tray icon - trillian, icq, aim, mirc if y'want, or even things like BulletProof FTP so you can monitor the progress of an active transfer or something - and it's done with a couple buttons instead of having to edit a config file and recycle :)

Check out the theme "Intuition", it should be in the Themes section by now.