For floor standing speakers in that price range, I strongly recommend the ER18 MTM speakers.
You can order the parts from
Meniscus Audio in Grand Rapids, Michigan. The version with the dome tweeter is $600/pair and with the ribbon tweeter is $681/pair. If sales for the parts kit is good enough, they might also sell an unfinished version of the cabinet. I doubt if they have one made now, but you could always ask. They also say the can sell a crossover board all assembled, wired, and soldered, but I don't know what they would charge for that.
If you want a pdf file that includes all the cabinet and crossover diagrams, parts list, and design details, send me a PM with your email address.
The two people who've built them and wrote about it on the AH DIY section are in Oklahoma and Virginia. Depending on where you are, think about contacting them to go hear them.