With all the frame builders we have here in our fair city (of Portland, OR), why is nobody building ALUMINUM RACE BIKES! There's obviously a demand for custom bikes. People even race their custom bikes. Aluminum frames make MUCH better race bikes than steel ones, and with all the carbon posts and bars people seem to like so much these days, you can pretty easily mitigate the rough ride of aluminum.
You know who rode a custom aluminum frame? Cipollini, during his comeback last year. Boonen rode one the year before, until Specialized changed the geometry of their entire line to suit him. If these guys can ride aluminum, you can too.
While our friendly neighborhood framebuilders are building some beautiful bikes. Steel is gonna be flexy as heck regardless of how well it's made. It's just the nature of the material. If steel is squishy by nature, racing a steel bike is a competitive disadvantage.
So, there's the ball, someone run with it. I bet you'll do quite well. And yes, Co-Motion has been welding aluminum since the days before custom bikes were cool. They never slowed Billy Truelove down.