Go back to square 1.
Tell her she needs to go sit on the potty every hour. DON"T ask!
If she pees her pants let her know you are upset/mad/dissappointed. she's old enough to know better.
Give her a new big girl sticker chart (I make my own) right on the bathroom wall. Give a sticker EVERY time she tries.
When she goes a 2 whole days without an accident give her a reward from the dollar store. After a couple weeks up it to every 3-4 days.
Talk to the preschool teachers, they may not be bringing her to the potty every time especially if you're sending her in pullups...get rid of them!!!
It doesn't sound like there's any real reason for her not to be trained by now.