The X10 mini might be different, but on the big X10, if you go to the applications and select 'Alarm Clock', then press the menu key (the one with 4 little squares on the bottom left), you can select 'settings' and 'Snooze duration' . From there, one can choose anywhere from 5 to 30 minutes, in 5 minute steps. I'm not familiar with the mini, but are there similar options you might be able to try...?
