I would love to see some features in PS that focused on web design mocking. Mocking complex lists/other common web app components are generally far more painful

I would love to see some features in PS that focused on web design mocking. Mocking complex lists/other common web app components are generally far more painful to do in PS than they are to style in the browser (though you still want to see those components in the context of the rest of the design before you really get down to business). A special layer type that renders its own HTML/CSS within the document would be insanely useful (or so it would seem).