Maximum systray icons per applications

[Controller]

I've managed to automatically restore systray icons on Explorer (re)start (and handle notifications during missing explorer). I now wonder

1) what's the maximum amount of simultaneous used systrays icons ever used by an application?

2) what icons does systray.exe provide. I know it supports the Unplug and Volume icons, has anyone seen the PCMCIA or USB icon in the systray?