Build my own speakers?

I am wondering if I buy the best components like scan speak-revalator tweeters and such if it can be possible. I am thinking it can for a fraction of the dealer cost of a new top of the line speakers made. With all the sites out on the web for cabinet design and such. Speakers with the revalator tweeter sale for $20,000 and up. The tweeter is only about $400 brand new.