IAB/IESG recommendation state /48 should be used in scenarios like this.
With earmarked allocations, as there would be no need to reserve space for infrastructure etc., a higher percentage than 80% would be easy to achieve.
It *is* For infrastructure, you can use a /48 (for Nerim, I have network infrastructure, servers, corporate networks and hosting on a /48 and I have spare space) For interconnection with the custommer, you don't need any adress (link local adresses negociated by PPP are good enough ; you can use /64 for that but link local is more simple I think) For ISP, IPv6 is simple. But big ISP will have a lot of adress space because they have a lot of custommers. (NREN will have less and hosting-only ISP will have a lot less when there will be a good mh solution) -- Xavier Henner Responsable de l'exp�rimentation IPv6 Nerim -- Fournisseur d'acc�s � Internet URL: <http://www.nerim.net/>