[Update: Available and shipping now] Satechi launches iPad Pro USB-C hub with HDMI, USB-A, and headphone port - 9to5Mac
Amazon.co.jp: Satechi 4-Port USB-C Hub Data Transfer Only (Not Support Video Output or Charging) (Compatible with MacBook Pro, iPad Pro, etc) : Computers
Add 6 ports to your iPad with this tiny, clip-on hub [Review] | Cult of Mac
Aluminum Stand & Hub for iPad Pro | Foldable USB-C Hub & iPad Stand