There are a number of different types of tang sights you can look at:
Thompson center has them for the Renegade/etc might work on your gun,
A short Winchester Tang I've seen on a Hawken with a little work done...
Lyman Receiver sight might be workable too.
Midway USA, Midsouth, Brownells all have sights. They run from about $50 to $500.
Aloha..
