I think I know what you mean but could you explain in case I've got it wrong please?
What do bipoles or dipoles do? To me that suggests that sound would be broadcast from two axis. I'd like to understand that better because I've seen it said that Monitor Audio's BXFX is switchable between bipole and dipole modes but I am not convinced that the author knew what he was on about. It probably would be best to have wide dispersal for the ceiling installation.
I want to use the height encoding for cinema viewing mostly. I'm happy with the distribution of sound at ear level as I have 2 x Heco Superior @ front, 2x KEF Q300 @ rear, Bower & Wilkins CM Centre @ centre and a Wharfdale SW150 sub.
Yes. I had already considered stands and the odd shape of my living room makes the stands impractical. I am not really sold on the idea of having large speakers hanging from my living room ceiling joists either. You have however given me an idea of the sort of enclosure that would be less intrusive.
I take your point about expense and £25 does sound attractive. I am still undecided whether to buy off-the-shelf, so to speak or whether to build. It would be hard to improve on those sort of prices but then I'd miss out on the pleasure of the build and its end result.