DIY. Whose speakers would you use?

Unless it's horn loaded, the transition between a 1" dome tweeter and 8" woofer is not a smooth one, off axis response will suffer in the crossover region.

If I were starting from scratch and considering 3-way, I would be looking at digital/computer crossovers with multi amps. Even an inexpensive Behringer 24/96 can be upgraded later. Perhaps even translate developed active crossover to passive to reduce overhead, once dialed in.

Kits:

http://www.creativesound.ca/

http://www.occamaudio.com/

http://www.selahaudio.com/

Found some more. With the exception of Visaton (German driver mfr) virtually no 3-way. Some interesting line arrays. No clue of your goals and budget.

http://www.visaton.com/en/
American distributor?

http://www.northcreekmusic.com/

http://www.zalytron.com/

Parts Express/Dayton

Mitch, there ain't no way I would pay that kind of money for a kit.

Take some relatively cheap speakers like "Polk". I went out to buy computer parts and came home with a pair of Polk speakers because they were so cheap. I'm in the basement listening to them now. They look cheap, they're made out of cheap material, but they are the best sounding cheap speakers I've ever heard. My point is this "The engineers at Polk know something I don't know".

Orpheus, What makes you think kits are not as well engineered as Polk or other products?