I've often considered the same question, there was an older version that used the old cupped BG Neo-3s (instead of the closed or open Neo3s)
But the most similar design-wise are the NX-Studio monitors, which use a closed woofer & an open-baffle Neo-3 tweeter.
The biggest consideration would be making sure the Neo-3 can meet the woofer and designing a crossover for them, but at that point, you've also gotta design a different cabinet, or at least mod the X-LS cabinet in a way to prevent the Woofer from influencing the Neo-3 tweeter. But it might require a horn or wave-guide to allow the tweeter to play down low enough and time-aligned to the woofer.
If you're into tinkering, and have a 3D printer, it's definitely something that could be considered as a way to explore, test and measure how it affects everything. It would be a fun project to explore, esp if you're stuck at home.