I think I've seen 3 at one point, but cna't remember what types they were. It will show any (or maybe just 1) all day appointments + the next upcoming one only, although I can't quite remember the logic for which ones it'll show... Wish there was some way to configure it.
EDIT: Advanced Config (
http://forum.xda-developers.com/showthread.php?t=418151) has a setting for it, but it doesn't look like there's a setting to show more than 2 events.