Dewayne,
I was basically thinking of something very similar to what you are describing EXCEPT, as Naysen mentioned:
"So far, I haven't managed to create something that will work for my difficult, terraced beds with external rock/boulder soil that will not take a spike for support."
Naysen,
Sorry to make things needlessly complicated. I get carried away at times
!
I just wanted you to know (in case you didn't already) that it's a fairly simple task to drill holes for your vertical supports into your concrete retaining walls (even with uneven surfaces) - if that's what you want to do. One just needs a hammer drill or impact drill and an appropriate masonry bit. These can be rented at places like home depot or a regular tool rental place, but probably easier just to hire someone (from a masonry or concrete firm) and have them drill a few holes for you. A quick web search shows lengths of 22" (which should be plenty deep enough) and hole diameters of 1" plus (and smaller) being fairly common.
The rest of the ideas/instructions in my post were just "gilding the lily"
.
And meant to confuse you
! (Just kidding
).
Anyway, good luck with things! Sounds like you're making progress with what you're currently doing.
Anne