Steve,
I have considered it, but its easier said than done. I have taken great lengths to design a speaker which integrates the dynamic and planar drivers for the best of both worlds.
The planar unit is only one part of a total package, selling just that part of the recipe to mate with an unknown would lead to a questionable outcome.
Full range planar dipoles are great, but I never felt they mated well with subs, and I always liked them better by themselves, sans subs. But after a while as much as I enjoyed the full range planar sound, I always wished for more dynamics and low bass.
Which has led me down the road to my current design. Greg