Forgive my ignorance regarding dedicated engineering calculators. My earlier reference to the Texas Instruments model had to do with the prevailing need for educational testing calculators that don't allow a lot of programming and can be "cleared". The model I cited is a commonly-approved tool for engineering school usage in the States, but would not be as useful for actual work as the other models in this thread.
Again, I believe that there is a niche market for the return of a product along the lines of the CFX-400. The open-source model Dave Jones offered should have been a wake-up call to companies like Casio, and I wish his efforts had become better known to the public at large during the time in which he was actively pursuing them. I recently saw a Kickstarter campaign for a "slide rule watch", which incorporates a circular slide rule for arithmetical calculation (as opposed to the flight calculation orientation typically seen in watch bezels). As I see it, if there's a genuine market for a slide rule watch, there should certainly be one for a scientific calculator watch! More functions, less novelty. The Citizen 9140A is another example of a scientific watch design that I think is fascinating, if maybe a little heavy-handed. I don't think these things should be merely resigned to the shelves of rarity collectors!
(That said, I love mechanical slide rules and wouldn't be opposed to owning a watch that also incorporated one into the design. Even in the absence of battery power, such a watch would still be intrinsically useful to some people, albeit a much smaller demographic.)