Dear Bryan,
This was discussed in dhammastudygroup and Pali expert Suan Lu Zaw helped us with this difficult passage about  viññāṇaṃ. 
We would think it means consciousness, but here it is different. It is participal and refers to nibbaana which is different from consciousness. 
Vijaanaati: to cognize. passive: vi~n~naayati. PTS also suggests it is participal. 
Suggested meaning: it is not evident, endless. 
Nina. 
Op 4 sep 2013, om 20:21 heeft Bryan Levman het volgende geschreven:

viññāṇaṃ anidassanaṃ, anantaṃ sabbatopabhaṃ.
ettha āpo ca pathavī tejo vāyo na gādhati,
ettha dīghañ ca rassañ ca aṇuṃ thūlaṃ subhāsubhaṃ?
ettha nāmañ ca rūpañ ca asesaṃ uparujjhati,
viññaṇassa nirodhena etth’ etaṃ uparujjhatī ti. 


"Where consciousness is non-manifesting, endless, shining everywhere, there earth, water, fire and wind, ...with the cessation of consciousness all this ceases."
Presumably the first viññāṇaṃ is a supramundance consciousness and the second (which ceases) is the fourth aggregate (or at least that's how Walshe interprets it on page 558 of Long Discourses),