I do not have anywhere near the budget or home for them, but have you considered GR series Tannoys? Low to mid 90s sensitivity, GORGEOUS....most beautiful speakers I've ever seen, resellable, and just plain amazing. I too also own and love the Buchardt S400 MKIIs, truly amazing speakers.....not just for the money.
I've heard (three times) the Tannoy Prestige GRF and the Turnberry GRF series at a client's home in about a 15' x 20' room with 9' high ceiling and reasonable treatment.....were driven with ARC vintage tube electronics. Only speakers that made me want to sell my house. Take with a grain of salt, I've never owned a pair of speakers more expensive than Thiel CS 7 series speakers.
Upscale Audio is the distributor, might be worth a phone call.