Use Mesh mode to create a "backup" link to APs

unknown

Hi all, i have to explain a simple question, my costumer would like to create a backup of network using mesh mode. All the APs will be powered locally, and not PoE. 
He would like to create an intelligent network that permits in case of "isolation" during the normal functionality by the cable network ( the switch goes down, fault etc etc) using the MESH. the mesh mode will be activated just in case of emergency, when link from netwrok will be down. 
do you think it s possible?
my configuration is with 2 cluster VSCG, 5 sites with 30-50APs each.