Hi, OP here. Thanks for all the replies. Unfortunately I don't have anything to show at this stage. I always keep rewriting this thing in different languages, then leave it to do some other stuff.

It would seem that the most efficient thing to do would be to develop a data entry + reporting solution for some vertical first, while keeping the back-end flexible enough that other verticals can be added later. It's just a matter of finding the right vertical (ha ha).

The generic DB idea has the virtue that to implement it one doesn't need to get out of the house, so to speak -- to go look for a specific problem in the real world and develop a real solution.

Thanks again, and if you can think of any vertical in need of an almost-generic DB, please let me know.