I suspect you're right on both counts: she's doing this for attention, and she's as tired of it as you are. The problem is that this bedtime drama is what has become her routine.
Here's one thing to keep in mind. Kids typically initially act out as a way to test the boundaries: what do I have to do to make mom/dad set the limits? Think of them as being inside a box. When they act out, it's as if they are pushing on the sides of the box to see where the flexibility is and how much there is. Some flexibility is fine, of course, but you don't want the side of the box to get too stretched out, because they have to keep acting out and keeping out, as if they are saying, "What about if I do this? Will that get them to set the limit? What about this time?"
It's your job to do this. I'd sit her down and have a calm and matter-of-fact conversation. (I know, I know, she's only 3. Try it anyway.) Keep it simple and brief: Bedtime has gotten out of hand. From now on, we will......and fill in the blank with the routine you want. It's OK to give her a choice or two: "Does she want to go to the bathroom one more time before or after the story?" Then make it clear what will happen after the final, scripted goodnight kiss. Tell her where you will be (in the next room, downstairs, etc.) Tell her it's her job to go to sleep by herself, and you know she can do it, and it's time now for some Mommy and Daddy time. If she cries, you won't be able to come to her, but you will check on her later. Ask her what she needs: a nightlight? soft music? stuffed animals? your picture?
By having this conversation, she knows exactly what to expect. She'll still test it out. Call to her from where you are: "I can hear you, I know you can go to sleep by yourself, I'm busy now, I'll check on you later." She's forgotten the stuffed animal? She can get it herself. If you do need to return for any reason (your call, obviously), be brief and business-like. She probably won't like this, but as long as you know she is safe (consider a gate), your job is to remain firm, consistent and calm. Once she sees that this really is the limit, she will feel safer.
I'm in the middle of reading a terrific book, "Bringing Up Bebe," that talks about how French parents deal with issues like this. I plan to write about it when I finish in more detail, but the basics are that American parents underestimate the capabilities of their young children when it comes to sleep and, as a result, we build in expectations that get us all, parents and children, into trouble.