Different view with what is a rebuttal to the BBC story.
Analysts: Pakistan Unlikely To Transfer Nuclear Weapons, Know-how to Saudis | Defense News | defensenews.com. Basically Pakistan couldn't weather the international storm and sanctions that it would suffer if it was deemed to have sold or supplied nukes to another country. Secondly, the article claims that Pakistan has avoided becoming involved in the Saudi - Iranian rivalry. Thirdly, Saudi Arabia is a signatory to the NPT and if this went ahead it would suffer diplomatic and possibly economic sanctioning. I don't necessarilly agree with the articles statement that Saudi Arabia doesn't have the technological know how. The Saudis have very deep pockets and I would suggest that it is possible that such knowledge can be bought.
If the article is accurate the Saudi's bankrolled the Pakistani nuclear weapon program so the Pakisani’s may feel they are under an overriding obligation. The Saudi’s could have had them anytime over the last 15 years. Why don't they already have them? Probably most to avoid upsetting the western powers that were their security guarantee up until now. Their participation in the NPT was on the condition that the Persian Gulf must remain nuclear weapons free.
According to the article Saudi Arabia apparently hasn’t asked for them yet. At some point Iran has to test its new nuclear weapon to make sure it works, that will probably be the trigger with Pakistan delivering the warheads a day or two later, and Saudi Arabia becoming a full up nuclear power with a few nuclear tipped IRBMs within a week.
But it is unlikely that the fun will stop there, because Kuwait, Bahrain, Oman, Qatar, and United Arab Emirates will all want their own as well, probably only a couple each, but that’s another dozen or so. Once the first weapon sale is made more are inevitable.
This announcement is likely aimed at multiple players. The primary targets would be the USA, EU, and China that if Iran is permitted to go nuclear, Saudi Arabia and the rest of the Persian Gulf will follow shatter the NPT and putting Middle East oil supplies at risk, so do something about it NOW! Iran is only secondary with the message that nuclear weapons will not buy them ascendancy in the Gulf.