Very interesting question, I would like to hear more about this. In my experience QlikView's licensing model is not compatible with this much users. A Information Access Server seems to be a possibility, but is very expensive ($70.000) in my opinion since I can imagine not all of the 72.000 will create added value from the data displayed. On the other hand, with that much users it's less then $1 per user.
I'm not sure how the Information Access Server (IAS) works, but I think if you need more than 5 concurrent users * $15.000 per concurrent user license = $75.000, it is cheaper to go with the IAS. There also used to be a very cheap license that allows one access per doc per moth to take care of the overflow, but I don't find this on the pricing site of QlikView.
As I see it, it all has to do with the profile of the users and usage patterns, some of which has been noticed in the posts above. Questions regarding users like
Concurrence ratio (how many people at the same time)
Business level (C-level, business analysts, mere listing readers...)
Developers (full access to all applications)
People with 24x7 access (developers, admins, CEO...)
Peaks of users in time (at the end of the month, closing fiscal year...)
In most cases, there is not a single good answer until you know all these points beforehand. And in all cases, is a mix of Named User CALs, Document CALs, Publisher + PDF Distributor license, Session and Usage CALs. The best you can do is to contact with your closer QlikView Account Manager or Partner and see in detail all the above and any other conditions to be met by the platform.
That application is running concurrently 72000 thousands of people? I think it is not. You should contact the nearest office and get advice. Access to the application for the business analysis will be used not as many people as you think. Else can provide offline reports in PDF / Excel. Automatically generate and distribute reports help NPrinting. If less than computers users can provide access to the computer. If users are working in shifts, you can create a domain user User1, User2 ... and for this the user will connect the user working at the moment..
72000 seems a very high number. Miguel is correct in his analysis. Break the numbers down and see what you would actually need. Miguel has posted in the past about Enterprise edition which deals with large volumes of CALs:
Since the IAS server provides unlimited licences, and $70K for 72K users works out to less than $1 per user, it seems the best value option by far (at least on the surface).
There are some limitations: You can only have one application, and there is no server authentication (this licence is geared towards pubic access via the web).
Also, you are probably going to need some really exceptional infrastructure/kit to concurrently service that volume of users concurrently* (* - dependent on your application size etc)
But like a numbers of people have already mentioned here, looking at your user base and how they will be actually utilising the application is probably a worthwhile exercise, and you might then find that the actual numbers are far smaller - and some of the other licencing options might start to make a lot more sense.