This Might Not Exist, Any reasonably priced, smaller speakers with 100db Sensitivity?

 I'll also add that there is another emerging category--the high power tube amp aimed at the 90dB sensitiveity speakers.

"Emerging"?  Hardly.

As has been mentioned, you couldn’t go too far wrong with a pair of used Klipsch Heresey’s or even the RP 600. Another Avenue would be to invest $59 in a pair of Lii audio F6’s and put them in an open baffle. I did this and used it with my flea tube amps and was sufficiently impressed that I went on to buy a couple other Lii speakers For more ambitious projects. Open baffle works really nicely with subwoofers in my opinion because you get the open air sound without sacrificing the deep base as you normally would have to. furthermore, I like the fact that you can use them for range without any crossover which keeps the efficiency high and also better preserves the integrity of the signal. to go on this level it seems like you have to get in to the large cabinets with folding horns or even a Voigt pipe design. These speakers come with their own demands on space, weight, and aesthetics.

Zu Audio recently announced the small Method bookshelf speaker.  94 dB sensitivity.

https://www.zuaudio.com/loudspeakers/p/mb1

Tekton is a good choice.call him tell Eric what you want he can heip.enjoy the search

I have a Triode Labs 45 monoblock Set amp putting out the most glorious 4.5 watts I’ve heard into large Joseph Crowe horns (105 db) in room. 
 

while these were being built for me, Troy loaned me a small wide baffle back loaded horn speaker that sounded magnificent in a near to midfield environment; so nice with the set amp that I bought it for my second system after I got the big horns.

look at his website and then call him; he might have something perfect for you.