Ever since I put a call out on Humanist for ideas around online publishing I have been discovering all sorts of systems and services. Scholarly Exchange is connected with Athabasca and charges a reasonable fee ($750) for hosting the workflow and publishing. They seem to support XML too.
Scholarly Exchange is the organization that provides the publishing service, but they are connected to International Consortium for the Advancement of Academic Publication which is more of an association. ICAAP has a portal for readers to get news on journals.