If SPAN interests you, you might try the Serval Mesh open source project:

http://www.servalproject.org/

https://play.google.com/store/apps/details?id=org.servalproj...

Admittedly the UI has not seen a refresh in a while, but the functionality is there.

Thanks. I'll check it out.

Looks to be a similar concept with a wildly different implementation. SPAN appears to operate at a much lower level.