I've done some more digging into this, and all three of you are right.
Pocket PCs suspend, Smartphones don't. This post explains in more detail:
http://blogs.msdn.com/windowsmobile/...01/446240.aspx
What I haven't been able to find out is whether Windows Mobile 6 has the Smartphone method the guy posting in that hinted at, or if that's for the next Windows Mobile.
For now though, it seems that the only solution for timers longer than 5 minutes is to not use the auto power off feature on non-Smartphones that don't use the Smartphone power model (or enter a system notification).
The joys of Windows Mobile development
