I'm surprised no one else has said that this sounds like a really bad idea. I guess you should work in whatever way you feel comfortable, but I don't see how this could work for any length of time. First of all my programmer mind says (or should I say object oriented mind), keep dependencies to a minimum. This approach sounds like having your entire application in one big .cpp file. That was one of the first wow moments for me when I was learning C++, having small little classes with 2 or 3 functions in their own little 20 line file. It's no accident that well written C++ applications have thousands of files. It is so much easier to modify a program when the one task (or several related tasks) you are working on is separated into one logical file. I've worked on projects where there was one huge file with 100,000 lines of code and functions that go on and on for pages. What a nightmare!

I don't think the organization of your tasks and projects is that different from a well designed program. How can you stay organized when everything in your life is staring you in the face all day long? It must be so distracting to have your Work to do list right next to your Errand list, which you can't do anything about at the moment. That's one of the nice things about GTD contexts, you have the list of things you can work on in front of you, the other tasks are in their own file to be opened at the appropriate time.

Computers have no problem with everything being in one big file, it's all just 1s and 0s, but the whole file and folder idiom was introduced to computers for a reason. The human mind does not work like a computer. It needs to have things organized and separated into it's own little slots.