I’ve been working with this on another project, and have manually made it work with Little Backup Box. Now there is an installer script in the works.
Basically, your Raspberry Pi will Join any network you have configured, and if no know network is found on boot (or by timer) it switches over to generating it’s own ad-hoc network (with a known IP address and a bonjour broadcasted hostname i.e. backupbox.local). From there, any wifi device can connect (presumably using a password)
It would be great if LBB could wrap this functionality in.