Does Stacking Wireless Speakers Sound Feasible?

Maybe not the same signal but certainly the same frequencies are emerging and interacting from up to three channels. 

Please stack a pile of LS50 wireless speakers...take a chance...I just want to see it...do it...also, what if an apartment neighbor has a pair of these things and his speakers pick up your front end and vise versa? Well? What?

One technical concern is that KEF embeds an "identity" code in the transmitted signal that keeps a stereo pair "private". Like using two identical subwoofers with remote volume adjust, there has to be a way to adjust volume one-at-a-time. Some remotes have an A/B switch to keep them separate. Like I said previously, I don't know what operating system KEF is using.
As to your stacking request, I'll gladly accept any contributions to make this happen! I suggest you send a pair of LS50s to "get the ball rolling"!

I think Tekton has dispelled the Comb Filtering myth...

What Tekton does in effect, is combine the output of the outer tweeters to function as one large mid-range transducer. The outer tweeters do not play the upper freqs, only the center one does. Because mid-range freqs are a longer wavelength, they’re less susceptible to comb-filtering effects when placed close together. If all the tweeters played the upper freqs, then the DIs and others using that array would indeed suffer comb-filtering effects. The main issue with stacking LS50s is the proximity of the tweeters.

The LS50s are capable of such wide dispersion that I can’t imagine you’d hear any subjective benefit from stacking a pair other than loudness.

Yes, loudness. That's what you pay the "big, big" money for (thanks Alex). Loudness and scale. Also, I never said I'd put them one-on-the-other. They could be separated by 12 inches or whatever. So in a room with eight foot ceilings, you could have a seven speaker array. Bet you'd get good sound out of this. Attention KEF: Please have this setup at AXPONA, O.K.? You'd sell a lot of speakers if this works! Remember: You start with a mini-array and add-on as you can afford. You could also sell the rack to attach them to.