you might consider a Rewel. http://www.rewel.com
This is an italian company (south tyrolean, to be more precise) that has years of experience (at least since 1988) working with Ti only and make *very* nice frames.
They have very competitive prices, the website lists 1350 for a stock Ti frame.
You can also have a frame made to measure, there's a web interface for posting your measures and they'll get back to you with a price estimate.
On top of that, they are very nice to deal with; a guy i know went there to pick up his new MTB-frame and the Rewel people moved the parts from his old bike to the new frame at no additional fee.
Martin, I sent Rewel a note with geometry, 2 days later the drawings arrived! These people seem very competent and professional.
Do you own a Rewel, or have experience with them?
How is the weld quality?
Are the tubes certified, do you know where the ti comes from?
They sent me a contact name in Boulder, CO. I wonder if they outsource their USA deliveries to a builder in the US?
I have sent all these questions to them, but anything more you could tell me would be appreciated. Thanks.