I don't plan to deploy IPv6 only servers myself yet (that day will come eventually).. however, there are a few edge case where I would like to. Enhance already support IPv6 just fine for websites (and for ssh login etc), I don't see there being too much code work to support IPv6 at an "Enhance" level.. ie website transfers (ssh), backups, mysql and all other services.
Already now some VPS providers will be starting to charge for IPv4. ISP's already do for static IPv4 (well, many ISP's).
I don't see this on the roadmap yet..