Hmm. With my old tired eyes, I don't tend to look for that sort of thing. Just because I don't know of any doesn't mean they don't exist, of course.
Heck, find some old, used Weaver or Weaver-style rings and make your own. They might not win a "thing of beauty" award, but if you're any good at penny-ante fabricating they could become "a joy forever".
AO Sights makes a ghostring site (not exactly a peep, but same concept) for a Weaver mount. So far, this and the NECG are the only options I've found..
Here's the project: I love my Yugo SKS's but need better sights for my sporter conversion project. And no, I'm NOT going to put an optic on the thing - IMO, it spoils the lines and concept of the lightweight brush gun. I've already tried a ghost ring drop-in replacement sight (Mojo) and that worked OK. However, the sight radius with the Mojo is shorter than optimum and frankly having the ghost ring sitting so far away from the eye makes it less of a ghost ring that I'd prefer. (It was really hard to focus on the front sight when the rear sight was so far away from my eye...)
What I'm doing now is buying a rear recoil cover with the built in low-mount Weaver base on it, and planning on placing a peep/ghostring sight on that mount. This should give me a rugged low-profile iron sight configuration with a decent sight radius and proper eye relief for the ghost ring. All I have to do is find/make the rear sight.
I'm actually leaning towards the AO ghost ring - it's not as good for detail work as a true peep sight, but should be better in the brush. It's also $20 cheaper than the NECG peep sight, and that helps.
Shouldnt AR15 back up sights for flattop's fit ok? There are a couple dozen options in that arena. How about cutting the rear sight off a detatchable carry handle? Thats among the better aperture sights in town (non micrometer of course).
J P Riflesmakes a quick sight that mounts to a picatinny rail. Its designed to mount on the forend but should work for a weaver. My understanding is that the Weaver and Picatnny differ in the number and spacing of slots on the rail They differ slightly in width but for pratical puposes it's so small that they're interchangeable.