A nice looking "Down for maintenance" page would be nice

The signup page is ok, but if you have not enabled signups, selecting a plan will result in a redirect to a page that doesn't exist, the 404 error page. Instead I suggest that you make a minor change and redirect signups to a page that is configurable. It could say for instance "The site is down for maintenance, please stay tuned. We are back in X hours." or something like that.