have you read my API suggestion implementation for managing projects?
Essentially I would use phrase-express to create a “!” parameter date like “3d#” for “3 days later remind me”. From there I would just tap into dynalist’s API to modify my tags / “!” dates at will using a dashboard panel
it would massively simplify “forced reminders” to myself like a lot of other todo-managers do, but I would have full control of it in dynalist.
its sort of similar to what you outlined here
Also, check out database models for project management:
found here: http://www.databaseanswers.org/data_models/tracking_progress_on_projects/index.htm