Have you considered the technical issues at hand with this idea?
Most existing wifi routers would need a firmware flash to support the correct mode on the NIC. I'm pretty such most mobile phone do not support this either by default.
Routers did requires some customization, but I think it won't be a problem if there is a financial incentive, especially there are already many linux-based routers that can use free firmwares like
totmato,
dd-wrt, etc that can add any functions you want.
For smartphones, iOS 7.0+ and android 4.0+ already have features required to implement mesh networking in you apps, and that's one of the reasons why apps like
firechat are so popular these days.