Looking back at this I think you are right that the specs that that a Domain will have a base URI per scheme. We may have been a bit over zelous with the base URIs in there association with bindings.
I'm just wondering why we assumed it was defined on a binding basis. I imagine separate base uris could be used as a convenient diambiguation technique for bindings sharing a protocol. But it seems that the Service Binding URI is intended for this. Simon
