Who makes coax speakers?

I'm  wanting to maximize vertical dispersion in my speakers so that I'm not forced to sit when listening. I understand that this limits me to coax or singledriver speakers, the later of which I already have and I'm looking for better frequency extension. My room isn't large enough to properly support omnis.

What brands manufacture these types of speakers, or anything else which would fit my situation? I'm aware of Gradient, KEF, and Tannoy. Likely to buy the Gradient Six speakers unless I'm missing a better option. Seas makes all manner of coax drivers but I'm unable to find any brands using them, why is that?