Electronic shifting is an option, there is also a conventional new XTR 11spd R/D and shifter.
For those of us in the US, check out Chain Reaction. I've got my pre-order in for the mechanical M9000 stuff for my wife's bike. Already received the cassette (gorgeous, but still not as nice as the SRAM stuff) and the shifter. Waiting for the brakes and the derailleur. *WAY* cheaper than the US based retailers. PricePoint mechanical RD: $238. Chain Reaction for the same one: $179. Yikes.
Had a great idea - have the 11 speed shifter and cassette - maybe this will work with the 10 speed derailleur! Just as I was about to start the experiment I realized I have the I-spec II shifter, which mounts to the brake lever. *rages*
The new Di2 looks freaking amazing, but when your new parts make XX1 look budget, oh my.