Which speakers, if any, combine the strengths of Harbeth and ProAc ?

Rockport and Verity Audio come to mind.

Verity and Reynaud

+1 for Vandersteen. I owned Harbeth speakers for years, various versions of the SHL5 and the model 40. I also had Proac Response 3's. For me the Vandersteen's do everything the Harbeth's and Proacs do well and build upon those strengths. My advice too you would be to go listen to any of the speakers recommended in this thread. Your opinion is the only one that counts. Good Luck!

Hard to go out and listen to these days. And I am not in a hurry, just thinking that I might want to go in this direction soon enough.
Vandersteen is very popular, and I am sure for good reasons.
ATC is interesting. Active or passive ? Which models ?
Verity and Reynaud..why not?
Rockport - too expensive.
Any of those can work equally well with both SS and tube amps ?
It is a common wisdom that Harbeth need SS and ProAc are better, generally speaking, with tubes.
ATC would need a lot of SS power, unless already powered, correct ?

@inna
" It is a common wisdom that Harbeth need SS and ProAc are better, generally speaking, with tubes." Says Who?
 

Harbeths are designed to present an ‘easy’ electrical load to the amplifier and will work well with valve (tube), solid-state and digital amplifiers. Playing loudly in a large acoustically dry, well-furnished room will demand a powerful amp. Conversely in a smaller setting listening closer to the speakers, much less power will be needed.