Ken,
>You will also find - in the end - that all your customer cares about (you know - the people who pay the money) - is that it "finds the price of their widget" quickly, accurately, and that they didn't have to pay you a ton to do it. Some of the most succesful VFP apps are horribly written from an academic or ideal OOP standpoint - but doggone it - they work and are making someobody money.
I have a couple of customers who also care a lot about maintainablilty and extensibility, particularly when the tightly-coupled design prevents an easy conversion to a web frontend.
I know you said that this discussion was not about COM, but was about Modal Forms, but the above comment ("all your customer cares about...") may be assuming too much when applied to overall app architecture.