[eluser]TheFuzzy0ne[/eluser]
I like Sweetcron. I prefer borccoli more, though. Budoom-tsssssh! (Sorry, bad pun, I know...)
Quite frankly, I am confused. I don't think I've ever seen so many software names in a single post before. (I know there's only three, but that's about as high as I can count).
I think you're going to have to build an abstraction layer between MetaWeblog and CodeIgniter's XMLRPC Server class. Alternatively, I think Expression Engine has support for MetaWeblog, so perhaps you might be better using that instead? It might save you a bit of a headache.
Hope this answers your question, even though I can't give you a working example as requested.