Ladajo,
Perhaps some given assumptions would be in order.
The entity building the weapons is intending to actually use them within a period of months after having fabricated sufficient quantity of devices thus eliminating the need for a command and control infrastructure and significant ongoing maintenance thus reducing both cost and complexity.
The weapons are intended to cripple the target's import/export shipping capability and induce as much collateral damage to the surrounding non-port facilities as possible thus allowing for delivery by ship and use of a non-miniaturized device. Cost and complexity are again reduce because a delivery system doesn't need to be developed or built (bought, leased, rented or just paying for freight delivery) and a simple, rugged device can be used.
Granted that the yield from such a device would not be as high as from a more sophisticated device and that more fissile material may be required to achieve a suitable yield. The yield only need be sufficient to achieve the destruction of the port facilities. The use of more fissile material would marginally drive up cost and time to produce the additional material.
I understand that these are not new ideas and have been well researched. I just want to make a point that there's a huge, huge difference in cost and complexity between building weapons to actually be used against very specific targets versus that required for a survivable deterrent that has to last for decades and can be used against a wide variety of targets.
Using North Korea as an example is intended to show what is possible by a financially strapped aggressor nation. Countries with a better financial/industrial/societal base would be presumed to be more capable in achieving their aims then the pathetic excuse of a country that is NK. And that leaves us with many countries that could be successful in developing nuclear weapons should they choose to do so.
Also remember the NKs are incurring a huge expense that they don't need to under these assumptions because they are attempting to build a missile delivery system. The expense of delivering a nuclear attack would thus be less than what the NKs have incurred.
India, on a per capita basis is certainly destitute even now. It helps when to have a population of a billion people in some regards (a penny here, a penny there and soon you're talking about real money). India was significantly poorer during the time of their initial weapons development.
Indonesia's large population was one reason I included them even though they too are destitute and don't have the industrial base of many other potential candidates.
South Africa actually did produce nuclear weapons and then later dismantled them although at least according to the Wiki article, not for cost reasons.
http://en.wikipedia.org/wiki/South_Afri ... estruction
Juvenile Weapons - kind of like the juvenile air force of 9/11. It's the effect that matters, not the sophistication. Using ships answers meets the need. No further sophistication in the delivery system is required. If they wanted to attack inland facilities, tractor trailers are again - sufficient.
Trinity was a test of the conceptual design of Fat Man not of the actual design of the Fat Man device. Much as lab work was used to verify the conceptual design of Little Boy.
I do frequently leap without looking
I prefer to look first most of the time. Consider though that the US effectively did so as well with those first bombs at least as compared to what today's design and testing practices would be. They were barbarian primitives
And yet the bombs still went boom.
I believe the answer to how many devices we had after the use of The Gadget (Trinity), Fat Man and Little Boy was zero due to insufficient additional fissile material. Why do you see that as a more interesting question? A potential weapons builder may decide that spending decades building their stockpile of fissile material up is acceptable. Some maintenance involved but not the same is if they were trying to maintain actual bombs.
Remember that the first one HAS been built and many more beyond that. The proof of concept work has been done the knowledge of how to do the work has been disseminated. It's now an engineering issue rather than requiring any scientific advances. This doesn't make it easy but it certainly is much, much easier now than it was for the first bombs.
Viable.... The main blocking issue to building a viable device is having sufficiently pure fissile material. For a rudimentary, viable device my understanding is they are straight forward to build.
Miniaturization and delivery vehicles. Your mindset seems to be locked there. Miniaturization and sophisticated delivery vehicles are not required however nice they might be. Step outside the box and think of an adversary that is actually intent on using their devices shortly after they are assembled.
I do have a layman's grasp of how difficult it is to miniaturize a nuclear device and develop, deploy and maintain a sophisticated weapons delivery infrastructure. That's why I choose to take a practical approach and eliminate as much complexity as is possible and stick to achievable goals in our discussion of a theoretical nuke builder.
I'm very aware of the fire damage that occurred and that incendiary bombs can be as effective if not more so than those bombs used on Japan. Incendiary bombs have the disadvantage of requiring a lot more of them to achieve the same effect. In an all out war they're an option. In a sneak attack that is designed to cripple an adversary in a short period of time the nuke is a much, much better option however primitive it might be. And potentially has the advantage of being untraceable if your weapons program is sufficiently well hidden.
Mildly chastise away
I'm a layman. Not a physicist or privy to non-public information although I have been following widely published information since the 4th grade. By widely published I'm referring to newspapers and not say physics or military trade journals that might have more detailed information.
Taking positions... As a general rule I'd advocate FOR taking positions on subjects even if you're not fully informed on the subject. As long as you're open to learning more, finding out you're wrong and willing to engage in discourse in a polite manner. All of which I try to do.
Think about the lessons to be learned from Lt. General Paul Van Riper's strategies in the Millennium Challenge 2002 war games:
http://en.wikipedia.org/wiki/Millennium_Challenge_2002
Take an approach of doing what you can with what you have. Not what you'd like to have or believe you should have.
How would McGuyver do it? And yes I know these are nuclear weapons we are talking about. But it's the attitude you approach the problem with that dictates what is possible.