Hi,
Maybe I misunderstood you, but I’ve already used something like this for years on WorkFlowy!
It’s the GTD Lite template!
I didn’t found it anymore on the WorkFlowy site… But you can create your own and read how to use it on the WorkFlowy’s Systems help pages.
GTD Lite System | How to set up the GTD Lite template
I’ ve extended the concept to my needs and created more filters…
Hope this help everyone!