Hi J.,
This sounds incredibly frustrating.
What I recommend to moms when the kid is 3 or 4 and it's at this point is to simply make potty training a "non-issue". Stop the rewards/incentives and punishments. They're not working for her, and this gives her a lot of control over the situation. She can show you that she doesn't care about your stickers, or that she doesn't want to go to an activity that requires her to be potty-trained, or whatever the case may be.
Have one, final potty conversation with your daughter. Tell her that she is 3, almost 4, and she needs to be going in the toilet, plain and simple. Tell her that if she decides to go in her pants, the consequence is that she must wash out her clothing and then take a short bath or shower. Make this routine as elaborate and cumbersome as possible without being cruel. She WILL get sick of scrubbing her own poopy underwear, but it could take several weeks or even months. Ask your daycare and anyone else who is taking care of her to support this consequence as much as is practical.
I would continue to give her "potty reminders" throughout the day, but that should be the extent to which you discuss the toilet. I also wouldn't *ask* her if she needs to use the potty, I would *tell* her: "It's time to go sit on the potty." If she refuses, remind her, in a calm voice and rather matter-of-factly, that she if she goes in her pants, she will have to wash her clothes and take a bath.
The whole point here is that this can become a huge control and attention issue for the child, and once they see that they are going to get ZERO reaction out of you, and that you no longer care about the situation, they will find it in themselves to things done. This is a trying time for you, but just remember that all kids master potty-training by the time they leave for college. ;-)
One side note, is to give your daughter lots of POSITIVE attention. When there is this type of friction in the home, sometimes it is hard to be around the child or to be patient with them in other matters. Find some time to do some fun activities and remind your daughter every day of how much you love her.