I think the basic idea is something that you have weighed in on in the past as not being a fan of. The idea is to be able to focus on any item without also seeing all the items which exist above it in it's particular tree.
If I have understood you, I think this might be something that you have expressed a willingness to consider in a future rewrite of the code in TaskPaper. That is, you discussed a willingness to look at sorting in a flat file type of way. If that made sense, that would also be a place to see something like what I have suggested here.
For example, lets say I have a project to do a presentation at a certain venue in a certain city at a certain date. The tree would be about doing the project. Inside that tree would be sub projects such as; Preparing end submitting the RFP (request for proposal), prepare the presentation, research the city and the likely audience or client, research the financial arraignments including travel and invoicing, prepare to bring items to sell or to market during the presentation, outside marketing or other opportunities to look into while visiting that city for the presentation (local radio spots, seeing relatives, meeting other potential clients, etc.).
In this scenario it might be useful to take each of these sub projects and see them at the top of your focus of your work in TaskPaper. If I am working hard at deciding what marketing materials would be ready then that is all I would want to see while I am working on that part of the project. I don’t really want to see that this is a project in Houston (for example), and that I have contracts to get signed, have travel arrangements to make, and that my presentation still needs polishing.
All of these things are important of course. But it is not possible in TaskPaper as it is now to have any of the sub projects start at the top of the TaskPaper page (as far as I can tell).
This is what I mean by hoisting an idea. I mean that I only want to see that idea at the top of the page at times and of course also be able to expand and work on any sub aspects of that project.
If I have not expressed this idea clearly, please ask and I will clarify as I can.