Please don't torture people that like classical and opera with a wimpy inefficient bookshelf... That's my opinion.
Do this:
Pi Audio 6 Pi Speakers: ($3500~ shipped I think)
These will have thrilling dynamics and good non-horn sounding vocals. They'll be alive, and squash little speakers. The only condition is they must be corners. But that's the good news, floor standing AND out of the way. They easily reach into the 30hz.
I would do this config:
Wood: Their choice
Finish: Their choice
Compression driver: B&C DE250
Woofer: B&C 12PLB100 (unless the Pi guy says it lowers efficiency, I would keep it 100db+)
Inductors: 15 gauge
Capacitors: Standard
Resistors: Mills
(
A review from someone who made their own at the bottom of the post)