Hi Rehd

From your description, I couldn't tell whether you already have it, but diagonal roving should be easy enough to weave through the frame and make it much more sturdy. It could be removable so the dome would still be transportable.

Here's a picture from the ultralight geodesic boats site that just shows the roving used to stiffen their hulls.

I'm sure I saw a hoop-house with something similar but couldn't find it.

Peter