perhaps instead of sleepy? whenever I see the word hallow(s) I think of the legend of sleepy hallow. There's also all hallow's eve. I would think the hallows would be a place, personally. Hallow also means to make holy. Actually, I'm rather curious if the deathly hallows could refer to that curtained area in HP 6 (at the end, where we lose dear Sirius Black---that really disturbed me).

also, a news article: http://www.chicagotribune.com/entertainment/chi-061221potter-story,0,5238548.story