Are you me? I had this exact experience, except after dealing with trying to resolve the conflicts with NATs and all the DNS pain that comes with a system having a different IP depending on where you are accessing it from, and the pain of re-iping an entire company, we actually DID go IPv6. All the offices still had their local IPv4 networks, but the mesh was IPv6 only. Turns out it was SIGNIFICANTLY less effort to get a new office IPv6 ready (usually just tweaking a couple toggles, occasionally replacing some ancient networking hardware) than resolving the IPv4 conflict.