Reading this thread (and I still use leapt as a matter of course: I leapt into action etc.) I note a couple things. First of all, in Old English, at the time when there weren't any "regular" verbs in English, just strong and weak ones, the vowels that turned into "ee" and "ea" in modern English (which Uncle DaveO referred to as "the exact same sound") were quite distinct; they have merged into one, but at the time that the irregular verb systems were being put in place they were not the exact same sound, indeed not even particularly close to each other. I'm pretty sure "bleep" is a modernism, and one expects modernisms to have regular tense forms, but "steep - steeped" does seem a bit odd, at least to an American mind like mine, brought up to think of tea as something quaint. And then in the matter of "creep", while "crept" is the past where it's a verb of motion (or near-immotion), I think in its modern use as a verb of emotion the past is "creeped":

The way he crept up and licked her calf really creeped her out.

On the other hand, I think in the case of sneak it's the irregular past, "snuck", that's the modernism.

Aye, laddies, she's an odd one that English language.

Haruo