Google Analytics (urchin) code snippets are already in your blogs for wordpress.com's own use. I hoped that it was something that was going to be shared, but seems that we have to be just satisfied with what they provide - a too simplified blog stats page (which currently hasn't been working for a few weeks). Also a script for another tracking purpose is at the bottom of each page which shows you a smiley.
I use Google Analytics and also hope to let it track my wordpress.com blog also but doesn't seem to be an option. You can't add scripts to your page. Assuming from that, the new beta version of Performancing Metrics may not be an option also.
People have been ranting about the non-functional stat page let alone the lack of information with the page. Stats are important personal informations but I think wordpress.com doesn't value that. Judging from the silence they had on this sole issue, maybe they're saying "If you're not satisfied, just don't use it and go to a service that supports them." (but actually stats is not all.. these days. The service is showing unreliable errors frequently (experienced another big time error an hour ago), but let's just ignore that since it's another topic.)
WordPress.com acted fast on things like adding youtube and so. I don't think adding options to include scripts for Google Analytics isn't much challenging than adding youtube. Also, the processing is done from google so there's no performance penalty to wordpress.com. I also think that stats have higher priority than adding widgets on templates(although this might be just my point of view). We're locked up in a stone age regarding stats. Is there any clear answer to why you are keeping quiet?
I sure hope that any representative can answer this and clarify things.