I would say that as far as tall buildings and second chances go in the middle of the map, it could only really be an item in the Gold Saucer or the Shinra Building. The game in the vents is something that is easier second time around... though its hardly the ultimate price... Anyway just some thoughts to see if anyone else can get it.
Ahh, now, here I'll steer you guys away from that line of thinking. "High over the earth" is relative. Compared to other tall things in this game, it's not really far at all.

No one's got it yet, but firmly on the right track!