@n80, GR Research sounds perfect for you. Danny Richie supplies the drivers, x/o parts, enclosure damping material, connectors, hardware, etc. He leaves the enclosure to the customer, providing he or she (yeah sure ;-) the internal cu.ft. volume required for the speaker design you order.
As you are content with your speakers (for now ;-), take a look at his subwoofer designs. He developed them in partnership with Brian Ding of Rythmik Audio, and they are something special. Sealed and OB/Dipole, both with Rythmik’s Servo-Feedback circuitry, and Danny’s paper-cone version of the Rythmik 12" aluminum cone-woofer. He provides the plans for his 2 cu.ft. enclosure design for the woofer, both a normal sealed version, and one with double walls, the space between them intended to be filled with sand, for damping of the enclosure walls. Advanced subwoofers designed not for home-theater use, but for music.