Jim Williams, an Australian builder, published an article in the GAL journal many years ago about a series of instruments he built using a similar approach. He made an extremely rigid frame for the top and within that had two flying buttress braces above a lattice on the soundboard. They sound qualitatively different from a normal x braced instrument but certainly not bad.
Here’s a video of a younger Aussie builder using a similar approach:
https://youtu.be/ahVkP15LtKE
It’s interesting but it looks complex to execute next to the construction we’ve become used to.