Well,
Consider me convinced! Dang dude, I would have never thought you put this much "math" into it. I am remarkably impressed.
Tell me what you think of this:
Using your tube technique, but leaving them open, adjusting the length to load the drivers enough to get the FS that one desires. Obviously an open baffle design.
Use the little B/G planars for highs. OB woofers like the ones from GR research for the lows...