shoot over to
www.samsung-omnia.org and look in the ringtone farm thread (or whatever it's called) and there's some extra loud alarms posted in there. you can always download audacity at
www.audacity.sourceforge.net and create your own. that's what i did. you can make them as loud as you want, save it as a .mp3, and use that to wake you up.
also, check out phonezoo.com and zedge.net for other tones. might find what you're looking for at one of those two places.
hope that helped.