You'd better read the book by Paul Williams called Osama's Revenge: The Next 911 and you'll discover that in all likelihood, AQ has purchased several (perhaps more) small so called SADM's (Special Atomic Demolition Munition's) aka a "Suitcase Nuke." These can vary from .2 to 10 kilotons. The Soviet Union admitted after it's collapse that they were "missiong" as many as 25 of these for use on our country in the event of all out war with us. These weapons have been (alledgedly) sold to AQ by (take your pick) the Russian Mafia, the North Koreans or rogue KGB agents. The asking price is waaaaay below "billions" of dollars. This intelligence has been independently confirmed by MI6, MOSSAD and NATO intelligence as well as the CIA.
HipShot can fill you in on how these weapons could be detonated and or activated and why the fissionable material is likely still good even after the fall of Russian communism.
Who do we retaliate against in the event of a nuclear attack by any Islamic faction? We turn Mecca and Medina into a new geographical area that shall be henceforth known as "Oil Under Glass."
It doesn't take billions of dollars anymore. Not even millions.
This may help as to why:
http://www.freerepublic.com/focus/f-news/1178024/posts?page=3183#3183