"Were any small (operational) stockpiles found in Iraq?"

For purposes of a terrorist attack that will kill hundreds to thousands of civilians the "stockpile" could be quite small compare what single artillery piece in a battle field could use up in one day. As far as I know, in terms of miltary use there wasn't found in Iraq any stockpiles that were ready to be used by any unit of the Iraqi army.

With that in mind:

'Reading from unclassified portions of a document developed by the U.S. intelligence community, Santorum said, "Since 2003, coalition forces have recovered approximately 500 weapons munitions which contain degraded mustard or sarin nerve agent. Despite many efforts to locate and destroy Iraq's pre-Gulf War chemical munitions, filled and unfilled pre-Gulf War chemical munitions are assessed to still exist." '
http://www.cnsnews.com/ViewNation.asp?Page=/Nation/archive/200606/NAT20060621e.html

{Please keep in mind that is concrete proof that Saddam violated the cease fire agreement.}

Also keep in mind that because of the quantity of chemical munitions so far found, it's reasonable that even now there still could exist more undiscovered chemical munitions in Iraq.

The "approximately 500 weapons munitions" weren't discovered in one location. If 500 weapons munition were found in one location that would be a somewhat large stockpile for a miltary unit, but would be considered a very small stockpile for an entire nation, but for terrorist group half of these munitions would be a very large stockpile. In other words killing holiday shoppers in a mall requires far less chemical weapons than killing combat units in a battle space.