Which Bitcoin exchanges publish proof of reserves?
Several exchanges have published reports (OKCoim, Kraken) but Bitfinex is the only one I am aware of to offer real time proof of reserves with individual BitGo wallets.

"The era of commingling customer Bitcoin and all of the associated security exposures is over"

http://www.businesswire.com/news/home/20150603005462/en/Bitfinex-BitGo-Partner-Create-World%E2%80%99s-Real-Time-Proof

Implementation plans exist so maybe more exchanges will follow:
https://iwilcox.me.uk/2014/proving-bitcoin-reserves

Proof of Solvency appears to be a similar term used by the industry