There is another path, which is to make 4130 bars. A number of builders make them, often in the time trial type deal, since those designs may have fewer hand positions allowing less flowing shapes to be attempted. Naked had some bars like that on their website, before they got famous, maybe still today... Also I would look at English cycles as they do a lot of bikes of that type, though I do not know to what extent they fabbed the bars.

http://www.englishcycles.com/customb...trial-machine/

One way to reduce some of the specialized parts you need is to make the bars fixed, and have a fabbed stem as part of the deal. That way you can make the transition to the steerer without having to worry about clamp sizes. You can also use bar end brakes, or thumbies, since these can be arranged independent of tubing diameters.

It is conceptually possible to bend thin wall Al tubing with only outside forming dies if you use the ice, or packed sand methods. Then, since the part is small, you might even get away with heat treating them in your oven. Have not tried this, while what Frank says, has many years of the real world behind it.