Meteor developer here -- we think it's super important to be able to serve static HTML when the situation calls for it (eg, crawlers.) Our architecture is designed to do this but we haven't had a chance to implement it yet. We have a lot of incentive to get to it soon, because it's no fun to be left out of Google :)
There's a bit more in the FAQ. Our approach is based on rendering the template as a string (it doesn't require building a DOM tree on the server and then serializing it.)