I've seen a video yesterday from Mac OS X 10.7 Lion and i have one impression - Apple is copying from Elementary OS.
Seriously, Apple from Elementary not the opposite. I see no point in emulating look of Mac OS X Lion in Linux, because we alredy have it's better version - eGtk. So if you are curious if i'm going to make Lion-like theme - I'm not. I really like eGtk and i think it looks even better than Lion.
But i'm thinking about making something inspired by original Aqua theme from Cheetah. Maybe i'll call it Cheetos But seriously - i really like original Cheetah Aqua, and i think it'll be my next theme (of course i'll be updateing Wildcat - it's my leading project)