I wrote my own alarm clock application (for the Apple Newton, about a million years ago) that addressed your need indirectly.
When the alarm went off, only the snooze button would work with a single tap. To turn the alarm off, you had to enter a numerical code.
And the snooze had a unique feature, too. Every time you hit it, it would snooze for half the time you got the last time you hit it, until that time reached 1 minute, at which point the snooze button stopped working entirely.
