M/Gateway Developments has released M/DB:X, an XPath-based XML Database with a non-RESTful HTTP interface based on DOM. There doesn't seem to be any support for queries across documents--you have to know the ID of the document you're querying--so it doesn't really replace a good XQuery database. There might be some use cases for this I'm ot seeing right now, but in general I think most projects would be better served by a traditional XQuery database such as eXist instead. M/DB:X is licensed under the GNU Affero General Public License Version 3.
