Yes. But it seems highly unlikely at this point that the courts would act fast enough to stop the electoral college process for 2016, let alone “overturn” the results of the 2016 election at some later date. That entails an entirely new realm of constitutional concerns about the separation of powers, etc. I think the most we can hope for on this path is a ruling that would prohibit WTA allocation in future presidential elections, which might be useful 4 years from now and beyond.
For 2016, the best course of action is persuading electors to exercise their prerogative not to vote for Trump on grounds of his conflicts of interest amounting to ineligibility for office, or on the ground that the college should not vote for a candidate other than the top vote-getter. This last approach would amount to an individual recognizing and applying the equal protection rights guaranteed by the US Constitution, even in the absence of a Supreme Court ruling specifically applying those principles to the EC+WTA system.
One of the questions I think I would confront if I were an elector (and not a dyed-in-the-wool party hack) is whether I have a duty to apply the “one person one vote” doctrine under the US Constitution, even if it meant violating my oath under state law to vote with my slate for the state winner. A supremacy clause-based argument would say that I do have that duty IF I believe that the OPOV principle applies to the EC+WC system. So I think I would feel compelled to vote for the popular vote winner.