Enabling Android as USB host on Galaxy Nexus or Nexus 10
I don't know the specifics about n10, but I found out an issue with my n7. When I bought it I got USB OTG/host working, but now when I tried with 4.2 it does not work anymore!

I found out that it was configured incorrectly. If you check /etc/permissions/tablet_core_hardware.xml you should see line android.hardware.usb.host in there, but after 4.2 upgrade it was not there anymore.

So for me it looks like the only way to get it working is to root the device. :-( I wonder why it has been taken out.