Has anyone of you ever thought abuot making a mac style taskbar in unity?
If yes, how did he do this?
Every ideas are welcome 
Do you mean an in-game ‘task bar’- or dock-style interface?
If so, you might check out EZGUI, which might work well for this. (Naturally you could implement it from scratch as well, but it would take a little work.)
if you are talking about a dock-style interface then I’d just port one of the hundreds of flash/jquery examples out there. Do a google search. All the tools you require are part of Unity’s GUI system or as mentioned above you could use something like EZGUI if you need onscreen performance for idevices.
Cheers.