Yeah, that's a really annoying problem.
Have you done any round pen training with your mare? That's basically what I do with horses that are tricky to catch. Get her moving in a circle around you, then, when she starts looking at you, step back and draw her in.
Because she just runs away from you, it's not quite the same as being in a corral. When I was having problems, I would use something my mare wanted, and make that the center of my circle or half circle. So, for example, I would stand in front of the water trough if she came in for water, and not let her get a drink until she came up to me and let me halter her. I'd just keep her going in a half-circle, turning each time she hit the end of the half-circle.
This didn't take more than a minute or two because we've done this in round pens before. I didn't make her run or anything - just walk and trot. I think she needed to know that I could control her movements.
Some people use oats, but personally I hate having to carry a bucket of oats to catch a horse. It can make other horses rude, too. For a while, I was setting the oats on the other side of the fence, out of the horse's reach, and doing the same thing that I did with the water trough.
Now I don't need to use any bait, but I do do the round pen stuff still every time I catch her. She yields pretty quickly. I also do it with other horses so they don't develop the problem.