Hi there, some survivor still breathing it seems,
I was ready to spend some time on the idea but it looks like it leads to a mixture of turmoil, expectations, conventions, implementation and layers of misconceptions. That looks like a collection of ingredients for a modern TV series ^^
Yes, what you expect, the way you described it, the fact it's not quite sure it turns out to be such a great idea after some time spent at trying to get used to it... Well, all that good stuff we like dealing with around here
My main concerns so far would be about how each application responds to dragging-zooming. There is no real standard way to do that, which leads to all the bad ideas each developer can manage to spread around soft-land.
Today I missed a nice mod of mine based on Autohotkey which allowed me to scroll the windows under the cursor rather than the one with the focus. The idea is simple, Autohotkey relies on Windows DLL to get the job done, so it works pretty well. But, depending on the application input handling, it may work or not. I don't remember why I deactivated it a few months/years ago... Well, I uncommented the include line from the main ini file and I will soon see what comes and hit me...
Zooming is even less a standard feature than scrolling. This means it would be absolutely necessary to be more specific at describing the means and the expected results you are talking about.
The Autohotkey event interpreter works in the Windows environment. It gives me the best programmable post-processing of mouse and keyboard events I've ever seen. Much more reliable than any bindings you can expect from manufacturers input software.
MultiTouch Utilities editor can do much more pre-processing than any other "driver" I know. This means that what you are thinking of is certainly feasible using such a combination.
If you are looking for a Linux solution, X input key processing will have to be used instead.
That leaves the task of precisely expressing the requested behavior and devising the means to make it happen...
Ready to shoot, with more crumbs...