Sorry, but no, I do not know of any way to export a static html site from mojoPortal. You might do a little googleing and maybe you can find a cms that does that, but generally content management systems are designed to take you beyond what is possible with static html. Static html has no way to enforce security other than file system permissions you might setup on the web server whereas mojoPortal and most CMS systems are designed for role based security and personalized user experience. While you might find something that can export html, I doubt very much that it will have features like contact forms, blogs and forums or anything interactive as these things all require some kind of server side code.
It's a shame they have such limitations, mojoPortal is used in other school systems including K-12 and universities.
mojoPortal requires ASP.NET 3.5 SP1 and one of our supported database platforms.