The W3C have spent a considerable part of their last meeting discussing how to speed up XML - see http://techrepublic.com.com/2100-10548-5630957.html?tag=nl.e606
The main protagonists seem to be going for a 'Binary' for of XML. This seems at odds with the purpose of a 'Markup' format. Futhrermore the stable door may being shut too late with various 'solutions' already in production. Looks like we may be back to multiple formats again.