I'd like that too. Using the website via phone can be a trial. However, a home made app is a recipe for more bug and update shinanigans, so I'm willing to put up with the browser for now.
I think that the mobile experience on browsers varies from fine for the forums (the forum software is very popular and used by many other sites) to not so good for the Live bit. An app is probably a bit much, and realistically refinements to the browser experience would be more useful for more people.