Marshal Will, I'm sorry I'm late to the party. I was going to suggest cutting the barrel down, to eliminate the loading lever latch. Sometimes it's the easiest solution. If you don't want to do that, I believe Track of the Wolf sells dovetail sight bases, without a sight on them. That would work to fill the dovetail, but would require fitting and probably a re-blue.
As for the sight, soldering a little taller post in is pretty simple. You could start tall, and file down as you sight it in. You may find it's not going to be as tall as you think. It's the easiest route, and is fully reversible if it looks hokey to you.
If you decide to do a dovetail sight, there is a jig for cutting the dovetail in with a file. It's not expensive, and it's pretty fool-proof. The name of it escapes me, but I'm sure it will turn up in a search.
If you're unsure about soldering the sight, just let me know. I have the full instructions, with pictures, up on another gun board. I'll be happy to direct you there if you'd like.