RFC: blow Ethernet-over-USB into a module

[Martin G-S]

> I don't follow Linux USB development closely enough to be able
> to tell if someone is already working on these things.

Kernel 2.6.27 will get usb gadget improvement, and a new composite  
framework as see in the 2.6.27-rc1 short-form changelog,  
http://lwn.net/Articles/291839/ :

...
David Brownell (50):
  ...
       usb gadget: split out serial core
       usb gadget: use new serial core
       usb gadget: descriptor copying support
       usb gadget: composite gadget core
       usb gadget zero: split out source/sink config
       usb gadget zero: split out loopback config
       usb gadget zero: use composite gadget framework
       usb gadget serial: split out CDC ACM function
       usb gadget serial: split out generic serial function
       usb gadget serial: use composite gadget framework
       usb gadget: RNDIS cleanups
       usb ethernet gadget: split out network core
       usb ethernet gadget: split CDC Subset function
       usb ethernet gadget: split CDC Ethernet function
       usb ethernet gadget: split RNDIS function
       usb gadget: new "CDC Composite" gadget driver
       usb ethernet gadget: use composite gadget framework
...