I'm probably Advocating Crime but, couldn't a bunch of people coordinate and do what he was doing, over a year or two, distributed, from several universities? You totally could. The more, the less noticeable, and punishable.
edit: it wouldn't surprise me if something like that showed up; the problem has been highlighted, the legal issues made clearer, and JSTOR bloodied. Go Aaron.
There's a loosely-organized project at Wikimedia Commons to liberate at least the public-domain works locked up in JSTOR. This almost certainly violates JSTOR access policies, but once downloaded and stripped of their JSTOR title page, it's probably not illegal for the Wikimedia Foundation to host the result, since the result is in the public domain, even if ToS were violated in the document's acquisition.
edit: it wouldn't surprise me if something like that showed up; the problem has been highlighted, the legal issues made clearer, and JSTOR bloodied. Go Aaron.