A TB who doesn't want to stand still...if I only had a nickel for every one of those!
Firstly, I understand your frustration. It's no fun to deal with.
What I'm thinking is, TBs are very linear thinkers. You're thinking stand won't still in cross ties while being tacked, she's just thinking about that first thing. Take the cross ties and tacking up stuff out of the equation. Stand her where you have a ton of room to manuever on a long lead line, 14' or so. Pick a time when you have all day to do this and it will only take 20 minutes. If you do it when you're in a rush, it will take all day. This is a guarantee. Ask her to stand still. When she ignores your request, either back her up, circle her, yield her hind end, whatever makes her work and focus on you. I'm not a big fan on high energy 'longe the crap out of them'. It doesn't get any point across and brings on focus on you. You want small things that make her work, but focus on you. Carry a long crop in the other hand, so you can make her back up or move her butt wherever you want it. Be assertive but not aggressive. Keep in mind you would be closer to the business end than if you were just longing her around, so stay away from her wheelhouse so you don't get kicked. That's what the long whip is for. Keep your energy as low as you can while still getting the result you want. When you start to see that look in her eye that says "oh crap, she's serious about this stuff and more bull headed than I am", bring her back to a stop and ask for her to stand again. If she stands there head high, rigid and just looking to move again, go back and get her butt moving again. If, however, she stops, puts her head down even a hair or gives any other sign that she's listening to your request to stand, throw a big party. Reward her with pats and lots of lovin'. Let her know she did right. Lather, rinse, repeat.
The most important part of the exercise is to be sure to reward the slightest try by her to stand still. The reward has to be immediate. You don't have to throw the big party after the first few times, but reward every try.
Once you've got this down in an open space, do it near the cross ties, but still on the lead. Then build more using actual cross ties, and then finally tack. Just make sure only only add one element at a time. Once she gets it, it should follow through, whether it's you or or farrier asking.
Hope this helps. good luck!
You just have to see your distance...you don't have to like it.