An 80’s band called The Unforgiven had 4 lead guitars, bass and a drummer who played standing up.
So, maybe 2 power trios at once??? 
Well, what if it’s guitar, bass, and drums with a very small groupie with only a broken castanet sitting on an amp just slightly off-stage…
Or, like 38 Special, with two drummers:
Piffle. The Dead had two drummers and I wouldn’t call them a “power” anything.
And the Allman Brothers, who had two lead guitarists and two drummers.
Several versions of Traffic were a trio.
I saw a local band comprised of three guitars, that’s it. They played only their own songs and they played hard.
No idea what they called themselves
I think that’s called a four way.
Just two? I saw King Crimson in concert a couple years ago, and there were three drummers. 
West, Bruce, and Lang are undoubtedly a power trio.
Hey, my band has 3 members - I guess we’re a power trio!
Of course, we are all in our 60s, and we play upright bass/clawhammer, guitar/fiddle, and cello mando! 
But we ROCK the old folks’ homes! 
In the mid '90s Robert Fripp reformed King Crimson with a lineup of two guitarists, two bassists, and two drummers. He called it a “double trio.” He didn’t use the word “power,” though.
Yes, I know The Who isn’t a power trio, but Glyn John’s breakdown of “Goin’ Mobile” is an example of how Pete, John and Keith sounded without Roger on vocals.
Speaking of power trios…
Hehehe, I was thinking of them when folks were mentioning that power trios were limited to a certain classic rock style, but I didn’t actually post about it. Certainly a power trio, and one of the best, (IMHO, of course). Thanks for mentioning them. Even though that track has four instruments being played at the same time through studio magic, I loves it. Plus, they could totally make it work without the organ.
But now that I think about it, one of my favorite bands was a power trio (after they decided they wanted guitar in the band). NOMEANSNO! Yeah, maybe one to rival Rush, even though they stuck to one instrument each (besides their voices). I kind of think the French have a way of making the best space rock, and now I’m starting to form a theory that Canada makes the best power trios. Maybe I’ll develop a theory of how bands seem to have more members as their home base approaches the equator! 
Either way, I don’t know how you’d describe this live snippet as anything other than POWER TRIO!!!
Plus. Best. Comedy. Guitar. Solo. Ever.
Seriously, the whole Live+Cuddly record rules.
I missed if already mentioned but Stevie Ray Vaughan and Double Trouble. A lot of sound from three guys.