Yeah, no question it's easy for a gmail account. But for your standard pop3 email accounts using the stock email app, there does not appear to be any similar option. I've been trying K9 for the last couple of days, and it appears that it allows different notification sounds for different accounts, so this may be the solution.
Still sharing the e-mail sync problems others have noted though. With 3 pop3 emails on the stock email app, only the first one syncs when the phone is idle. The others don't refresh until you pick it up and open the app.