Firstly, radioactive sources capable of being used in dirty bombs can be found in any University - I used plenty myself as part of my Physics degree. They are also common in hospitals. I would suggest that many of the '1,000' sources removed from Iraq fall into this category.
Secondly, nuclear material is easily traced unlike common explosives. If Saddam had chosen to supply an insurgent group with material for a dirty bomb, he would have effectively signed his own death warrant. The man may have been a genocidal maniac, but he wasn't suicidal.
Thirdly, the Uranium found was low enriched material. It was obtained from the Tuwaitha Nuclear Research Center, which had been annually inspected by the IAEA for several years. Their audit essentially consisted of an annual material stock check and they were aware of its existance.
It was removed to prevent proliferation, amid reports of looting of the facility after Iraq fell. You might argue that prior to the coalition invading, it was far more secure than after, hence its removal from the country.
Sarin gas does not require an ellaborate manufacturing facility. I seem to remember the incident you refer to was the detonation of an old artillery shell.
Given that Iraq once had significant amounts of chemical agent during the Iran-Iraq war, its hardly surprising there was some left-over. How does 1500 gallons and a few rusting shells compare to the huge amount Iraq once had, and then subsequently was forced to destroy?
Maybe your definition of WMD differs from mine - and I think my goal post comment is still relevant. Mass destruction isn't disruption of the rush hour or inconveniencing commuters - its murder en masse. A nuclear explosion in a city centre or a dispersal of chemical agents that maims and kills large numbers of the population. Where is the evidence that this could be achieved?
Importantly, and I think this is where your misconception lies, there has to be a method of deployment. Tony Blair may not be your representative of executive power, but he was a key supporter of Bush. Bush relied on him towing the line and by having a significant international ally, it lent his arguments a more international and balanced gravitas. He publically quoted from a dossier that stated:
...chemical and biological munitions "could be with military units and ready for firing within 45 minutes."
The WMD argument for war was flimsy and has not been substanciated since. Even the staunchest of proponents of this argument now maintain they were just wrong, but no lies were told.
Except those that would maintain the possession of a can of mace spray was a material breach of the regulations Iraq was party to concerning WMD control...
