Holy CRAP she conquered the stairs! I'm so happy!
Since that storm moved through a couple of weeks ago, I've been working on her regularly trying to coax her up the stairs - and doing it in a way that was on her pace and her terms. I knew I could probably force her to go up, but I didn't want to do that. Anyway, as I was getting ready to go up to bed last night, she was standing between me and the stairs and I thought, "I wonder what she'd do if I just lightly tugged her collar and guided her up the stairs? What the heck, let's give it a whirl." So I tugged her collar a little bit, nudged her with my legs a little in the direction of the stairs, and lo and behold, she climbed up to the landing all by herself! I couldn't get her past the landing, but what big progress! I was so proud.
Well, earlier today I went up to retrieve my water bottle out of the bedroom. I thought it would be another good chance to reinforce the whole stair thing, so I called her up. She hesitated a sec, but then came up to the landing completely under her own power and without me touching her. But she did something different this time: rather than plopping down on the landing or turning around immediately to go down, she sat down. She looked down towards the ground floor, but then I called her name and started coaxing her up (I had already moved all the way upstairs by this point). She hesitated and looked down at the ground floor again, and then she stood up. I called her name again and patted the floor and told her to come, and HOLY CRAP!!! She climbed up the remaining half of the stairs!!! Once up there, I praised her heavily and gave her a jerky treat, and she proceeded to hop right up on the bed. It's all over now - I'm going to be fighting the giant for bed space from now on. 
I'm so proud! One huge fear conquered.
I'll be working with her another few times today to reinforce the accomplishment, but I fully expect her to join me upstairs tonight.