I agree, your light elements were fantastic, and I too wanted to duplicate your work -- or build from your ideas!
The panels that you used do not seem to be the same as what Sean found... so if you can locate ordering info, that would be great.
Also, the flex strips you used did not seem to be the waterproofed variety with the sealed vinyl/rubber/plastic covering. Instead they seemed to be "naked" without the extra covering -- which I see more in dumb RGB strips. What did you use? With a sealed panel, i'd think that the covering is unnecessary and also forces a larger spacing to be needed.
I've also been unable to find the pex. I found something in a roll that was much thicker and didn't let light pass through as well.