This restriction from the ESPN FAQ:
How do I get access to ESPN3?
ESPN3 is available nationwide, but you must subscribe to a participating high speed internet service provider.
and after scanning the ESPN Terms of service at:http://corporate.disney.go.com/corporate/terms.html
I find nothing other than the provider restriction to limit ESPN3 to certain boxes so, it seems, that a ch is at least possible.
The only problem I see is that the streams seem to go to the lowest possible quality after a short time fairly often even though I have plenty of speed available.
We can only hope that a kindly developer finds a way to get this done.