The android ADB debugging protocol includes the ability to forward UNIX sockets over the usb link, so your phone has this facility built in.

http://developer.android.com/guide/developing/tools/adb.html...

Unless I have misunderstood the adb docs, it shouldnt be too hard to set up, even though it only seems to allow ports to be forwarded from the host to the phone, rather than the other way around. Nimble use of netcat/iptables should remedy this.

EDIT: people seem to be calling it "reverse tethering" and while it involves the adb, it doesnt use the port forwarding. See: http://blog.mycila.com/2010/06/reverse-usb-tethering-with-an...

Pick any USB Ethernet adapter supported by Linux, and it should be fairly easy to get it working on your rooted phone.

Here's some code showing how to mess with networking on Android: http://code.google.com/p/android-wifi-tether/

Unfortunately not. Android devices are not yet capable of acting reliably as USB hosts. This means you cannot connect peripheral devices to them.

The IOIO works by acting as a USB host itself.

I've seen android prototype devices by vendors for demos and they have ethernet ports. But I guess that's not a usb interface either, it's native.

One of those G's isn't enough? 3G? 4G?

Bandwidth over 3G or 4G is rarely free; bandwidth over wired Ethernet very typically is.

no cell or wifi communication possible, but ethernet available

I've seen a usb tunnel for iphone but never anything for android.