I have a pair of trio 15 TB.Have you heard them? Have you seen any measurements on these? I think with the modelar concept, it is possible to choose a combination suited for smaller rooms. What open baffle is concerned, there are either the smaller ones from Spatial audio, like here https://www.spatialaudiolab.com/qseries for example, or these from PureAduioProject: https://pureaudioproject.com/duet15-prelude-open-baffle-speakers/. In any case interesting concept.
One big problem they have (which might be better dealt with in newer versions) is panel vibrations. They do need bass support under 50 hz. The off axis null in bass makes them easier to place than other speakers, but you need to be 3’ from the wall.
There are several versions of Center panel for different types of mid/hi drivers.
I think you could make a better pair using sb drivers (as Joseph Crowe demonstrated on his site) less expensively.
DSP cross is good here as power requirements for bass >> fullrange.