If you are good with tools it wouldn't be all that hard to make something. I make knives sometimes, and working with brass for hilts and handmade rivets and such isn't terribly difficult - it's nowhere hard as steel. Or copper is even softer, I believe.
1) measure everything carefully
2) get a piece of brass or copper that is as close as possible to the size you need
3) unscrew the rear sight
4) remove metal from the piece that you are working with until it will fit snugly into the little notch/slot/trough that the rear sight fits into
5) remove metal until the top of your little piece in the back is just the height that the original rear sight was
6) put in a groove/notch that you will look through in your new rear sight
7) remove metal until the most forward part of your new sight is flush, or close to flush, with the gun barrel - you will probably want it to gradually slant down from its high point at the rear where the sighting notch is to the low point in the front where it is more-or-less flush with the barrel
8) very carefully drill a hole so that it will line up with the hole that the original sight screwed into
9) you will probably need a new, longer screw to install it, or "counterbore" the new hole a bit so that the old screw will fit
10) voila! you have a fixed sight!
Sorry for the long crazy instructions. I have a small 32 revolver that I wish has a fixed rear sight, and while reading the OP I realized that I could probably make one. The above is sort of an outline of the half-baked plan that popped into my head. If anyone has suggestions I would be happy to read them. I am off work for the summer (school teacher) and it would give me something to do.
