badbadmonkey - 3:44 pm on Jun 28, 2011 (gmt 0)

Maybe X-Robots-Tag: unavailable_after: #*$!x, to tell Google when it's going AWOL, then just remove the tag when you're back in business. In the meantime you leave the page response as 200, the content has changed maybe but the page itself as an entity hasn't, or it shouldn't (replace content with a "sorry" message) - I don't see a legitimate reason for using another code. What you want is a semantic requirement, the server codes have technical meanings.