There was some speculation on my personal blog (here and here) to this effect back in February.
Would Hillary accept a Supreme Court seat? On the one hand, it could certainly assauge her thirst for power. On the other, as I've thought about this possibility since February, it's also seemed to be that she's hungry not just for power -- but for the constant, public validation and the conflict that accompany a career in elective politics. Would strictly intellectual combat, in a pretty cloistered environment, be enough for her?
Finally, are there any conflict of interest issues that might arise? After all, Hillary Clinton played a great role in staffing the Justice Department during her husband's administration. Could she decide with an open mind Supreme Court cases that implicate issues (or cases themselves) that were litigated by the Clinton Justice Department's solicitor general?