With my limited Mason experience, I don't think you can without doing it yourself. My understanding is that Mason's wrapping chain mechanism (i.e., finding autoload, etc.) is implemented in its ApacheHandler, which acts as a controller to find the actual component. In CGI mode, Mason is pretty much a template engine.

As to integrate bloxsom with Mason, bloxsom is a simple (yet flexible) cgi script. Once you introduce mod_perl and Mason, it's pretty easy to write the whole thing in Mason, seems to be too much trouble to wrap it. In other words, it's probably easier to write a Mason port of bloxsom than to wrap it.