Another idea, a little complicated, is this. Does somebody make a weaver -style base mount, that clamps onto the receiver groove instead of having to be held down with screws? Check Brownells.
If so, then once a short weaver base is installed, I'm pretty sure that somebody makes a high grade peep sight, that clamps right down into a weaver base. Again, check Brownell's. I think NECG makes one.
Of course, you would have to put a pretty tall front sight on the rifle to match up with the peep sight, but it might be a good result.
And, also, the cost of the base plus NECG sight may be more than the original cost of the rifle. But, it would probably be cheaper that the cost of full scope mounts, rings, and a high quality scope.
Mannyrock