Have you considered Madisound? They have a good reputation, offer quality parts from drivers to crossovers and other parts, along with cabinet plans.
Audio Note Speaker Kits
I have wanted to build a pair of speakers and have access to a complete wood shop. The area where I lack expertise is choosing and matching drivers and designing a crossover. What really appeals to me are the kits that used to be available from Audio Note. Unfortunately I'm a day late on that since they are no longer available, so I am appealing to the Audiogon crowd. If anyone has a kit they want to move on or know of where I might find one I would be very interested. I am particularly looking for the AN-E series kit. If anyone has a line on one please let me know and thank you.