Given the large storage mass involved, preventing temperature fluctuations without being at the exact boiling temperature of LN2 is feasible; it could be both highly failsafe and use the ideal cryonics temperature of -135C rather than the -196C that LN2 boiloff as a temperature regulation mechanism requires. Feel free to raise further issues in the comments.

Wow, that's incredibly attractive - it would completely eliminate cracking as we pass through the glass transition temperature. I take it that would also reduce LN2 costs by a further 30% or so?