Unless you really want a 40mm lens, I can't imagine that the Ultron would be worth the money. For less than $250, you could find a used 35mm and a used 50mm, both top notch Nikkors in excellent condition. If you stick with pre-Ai lenses, this is easy to do.

KEH has a Nikkor 35mm f/2 pre-Ai lens in Excellent condition for $115...this is the version just before Ai lenses came out, so it has the 52mm filter thread and is multicoated. In my experience, KEH's Excellent is close to what most people consider mint. (One of the images in the 2006 Nikon calendar was shot with an F2 and a Nikkor 35mm f/2 lens...it really is a great lens.)

If you want a normal lens, don't discount the Nikkor 50mm f/2 lens. I have a number of Nikkor 50mm lenses, and the f/2 is actually my favorite. If I needed the speed of a 1.4 I might think otherwise, but I find the images from the f/2 lens to be more pleasing than those from the other Nikkor 50mm lenses. You can get the 50mm f/2 in late pre-Ai (52mm threads, multicoated) from KEH for $65. If you want speed, the 50mm f/1.4 late pre-Ai Nikkor will set you back $79.

If you want a 40mm lens, then I think the Ultron is your only choice in a Nikon F mount. But if you can live with a 35mm lens, a 50mm lens, or both, then there are a number of very highly regarded Nikkor lenses at those lengths. Plus you'll pay less than you would for the Ultron.

Best of luck.