I use rEFInd, but I never used boot-update or similar abstractions.
I think that rEFInd will and should never be in portage, because by its nature it's something that you need to install manually: it goes on the ESP partition, not in the usual system partition(s) (/, /usr, ?), and it's independent from the installed OSes so why should Funtoo manage it? It could lead to problems more than solutions.
@Chris, not everybody uses the same color theme here: your example is unreadable on my white background until I select it.