You might consider something like Paul Dressel has done. This is a 358 on a Grisel Mauser action with, what appears to be, a 20 or 21" barrel. He's using QD mounts with fixed open sights.

While this rifle is as custom as it gets, fully engraved and exhibition grade walnut, the idea is similar.
There are quite a few peep sights made that attach to the bolt and fold down when not in use. These were quite popular and fairly common several years ago, but as popular today. I believe they are referred to as the "H&H Bolt Peep sight". Tom Delucchi is manufacturing replicas that are true to the originals. I don't have a picture of one, but believe it is exactly what you are referring to.