Looking for a way to manually sort next-action items from multiple projects

I have, say, 20 projects. They are all well organized with hierachies of tasks, defer dates, due dates, etc.

I’m searching for a way to do the following: I would like to be able to plan (eg, plan projected work for today) an ordered super-set. So I would (for example), select ‘the first item from Proj A’, then I’ll do the ‘first item from proj B’, then this item from my Inbox (no proj/no context on that one), then I’ll do the second item from Proj A.

Contexts almost do this… I could create a “today” context and set that on everything I wanted to do today. But, a) that wacks my contexts and b) it cannot be ordered from within context view.

Flags almost do this too… I can easily flag things I want to do today. (Aside, I’m not currently actively using tags for anything.) But then in the Flag perspective, I cannot sort manually - can only sort by Project or Due. I could manually tweak all the due on each task, but that’s tedious, and then tomorrow I’d have to rejigger them again. Also, sorting in Flag perspective only sorts within each context. I’m hoping for a single list of ordered tasks, where that list is drawn by cutting across all my projects.

…does what I want make sense? I’m trying to front-load all my day planning so I can start doing things, then tomorrow, I can add more (maybe by flagging) and resorting…

So far, flagging and setting the due dates is the best idea I’ve come up with.