you could use "ContainerFrameItemButtonTemplate" instead of "SecureActionButtonTemplate".
clickability to use items
non secure (prevents taint)
can handle show / hide / positioning even while in combat
you have to create a header for each button (but thats fairly easy to achieve)
Edit: I'm going to prepare some code and explanation for you later... currently at work!^^
Thank you so much I look forward to it. Gonna play with ContainerFrameItemButtonTemplate for a while see what i can see. Maybe combine that with table.insert as buttons are created as per Fizzlemizz's suggestion, so we make tables like you suggested, and we may have something.