A "Render to HTML" feature isn't possible because the whole design hinges on the site itself being used as its own editing interface. So at a minimum the page has to determine whether or not to present the "Edit this page" link.
The final requirement (for performance) says that there needs to be some caching, so that if you request the same page multiple times, we're not sending many identical queries to the database to get the content for that page. That probably involves writing a scheduled proc that goes through the cache and culls anything that has expired - we don't want all the content requested in the lifetime of the server process hanging around in memory.
With cached content from the db for each page, performance benchmarks should be competitive with any other templated page. And since the templating system compiles ADPs into bytecode, they perform pretty well.
