There just aren't that many great ways to customize alerts/ringtones/etc yet-- that'll be a future release of the PalmOS I'm sure.
One hack I came up with, since I must monitor job logs for my work as well (sup IT buddy):
1) Set up a new gmail account (baxtardALERT10248@gmail.com)
2) Add a rule to your corporate inbox to forward joblog alerts to your new gmail account
3) On the pre, add your new acct to the Mail accounts (click Mail icon, then upper left, "Preferences & Accounts")
4) Under your new acct on the pre, you can specify "Play Sound" for when you get a message.
This is a crappy workaround but it'll give you a fighting chance to get notified as soon as you receive the message with what we currently have.
I'm sure sometime in the future someone (or Palm) will deliver us some flexibility & options, but for now we've gotta hack