Where could I purchase Network Operation Center (NOC) equipment from a bankrupt company or used/surplus?
With the number of companies that have closed their doors recently it should be possible to find real deals on network equipment of all types - including NOC systems. Corporate bankruptcies are complicated, with lots of creditors involved. As such, there are companies that focus on liquidating the assets post bankruptcy. Do an Internet search on 'Bankruptcy Liquidation' and you'll find an impressive list.
I would also watch online auction sites like Ebay, as there are many companies that are downsizing and Ebay seems to capture a lot of this business.