Hi nemik,
Thank-u!! I´m doing the same as you (not directly because is 3v3). At the moment, I´m triying only with DD-WRT, in stead of OpenWRT, because it has an easy configuration web page.
I also try to do the router programmation using bash scripting.
The idea is to have a "generic hardware" for the prototype phase of an electronic project (always trying the easy way to resolve things).
What have you done with arduino+Fon?
Kind Regards, 
Igor R.