sweave tables as images?

If I understand it correctly, odfWeave doesn't have a path backwards
from the odf doc back to the original odfWeave doc (which is the main
restriction of all these Sweave/knitr/etc solutions in my use case).
Please correct me if I'm wrong about that!

Unfortunately I cannot help you with this specific question, not least
because I've never used odfWeave.

From a quick glance to the docs, it seems that you always have two

documents: source odfWeave .odt (equivalent to .Rnw) and output .odt
(equivalent to .tex). Then using the .odt (.tex) you can generate a
PDF. I would be surprised if it were possible to go back from .odt
(.tex) to the source .odt (.Rnw).

I would suggest that you contact the authors of the respective
packages to make sure that the functionality is (not) available.
Regards
Liviu