FWIW, NH's version of the tool (with its 90s-era UI and all) appears to have a generic URL in which the host airline (the one whose miles you're using to upgrade) can be changed. The catch is that only a handful of *A airlines enable this version of the tool, some decidedly more useful than others. So far I've found working links for TK, MS, ET, SA, and OZ. In case anyone has access to any of those currencies and wishes to try an online *A upgrade.