I just bought the new Logitech K811 Easy Switch bluetooth keyboard. Lovin' it so far. Looks like the Apple keyboard with aluminum chassis but has black keys to match my iMac and they are backlit. You can manually set brightness level or leave it on auto. Rechargeable as well and includes USB cord for recharging.
I ordered mine direct from Logitech as nobody seemed to stock it yet. (brand new model) This is designed for Mac and has the Mac keys. It can also easy switch between 3 x bluetooth devices so you can quickly use it for iMac, iPad, iPhone.
http://www.logitech.com/en-ca/produ...y-Switch_Keyboard_for_Mac,_iPad_and_iPhone|hp
Cheers!
P.S. Not to be confused with the similar looking K810 which is designed for Windows.