I know OpenERP SaaS does not accept any custom module.

But maybe some specific customers are willing to have a SaaS option with non-official modules (always the same ones). (For customer to whom official SaaS is enough I would not go through this and recommend the offical OpenERP SaaS service).

So, instead of just installing OpenERP in a virtual or cloud server for each customer, I just wonder if it is possible to set up our own SaaS service, what would it imply and how could it be achieved. Any hint, tutorial, manual?