I had a hard time last year looking for the same thing. I finally got one at my LBS but I was lucky. It was not a bladed fork though. You may have to settle and go for a threadless headset. There were if I remember correctly still quite a few threadless 1in forks in my internet searches.
rock lobster, rock lobster, serotta, ritchey, kestrel, paramount
if you really want a striaght fork, check with paul at rocklobstercycles.com, it seems like all his bikes have a straight fork, but the current crop has 1 1/8", but he would be a good source to find a 1".
On another note, can I just purchase a 1" threadless fork with a steel steerer and get it threaded? Or, is that just insane?!
I've read that this is a bad idea. A threadless steer tube has thinner walls since it doesn't have to take the pressure of the expander on a quill stem. So you'll end up deforming your tube when you tighten your stem. One possibility is to have a frame builder cut the tube down and weld on a thicker tube that can be threaded and take the stress of the quill stem. But you'd probably end up spending more money than it would be to just buy a 1" threadless headset and stem.
Another idea would be to get a good threaded steel road fork for for cheap, braze on some canti studs, and repaint.