@Idolwild and others,
Although this is a somewhat older thread it might be interesting to look at this one Master board linked to multiple low-level boards - #3 by jakobrydberg
The Rollup Multiple Boards app let you create multiple “down level” boards where the connection is maintained in a database. In the high level board you can have recipes that does a rollup from all “down level” boards. So it basically rolls up an entire column in any number of “down level” boards to an item in the high level board.