The main page link predates this system, and is used in a few other places under the 'mainpage' name.
Yeah, about a dozen, not counting language pages.
Hypothetically it could be changed, though...
Obviously, there's no pressing need. It'd be nice, though.
Try: array('text' => 'mainpage-text', 'href' => 'mainpage')
Clever. Your answer is like my third option, only better because it saves one redirection. I'm puzzled why I thought of changing the 'href' page and not the 'text' one... :)
Thanks,
/L/e/k/t/u