I can relate-it's tough to be in your situation! I also had a biter at the same age-sad to say she didn't end this phase for almost a year-it was awful. Like you, I tried everything, and only learned some things after the fact from a woman who had researched kids biting.
1) Try to find the reason for the biting. Is she tired? Hungry? Frustrated? Doing it for attention? Is another kid doing something to provoke her? Where does it tend to happen, when, and why? See if you notice patterns and respond accordingly (ie If it's because she's gotten overtired, make sure she gets plenty of rest. If it's because a certain kid always grabs at her-deal with that angle.) With my kid, she always bit in very public places like parks, and she was telling me she'd had enough but I wasn't getting it! She also pushed kids down-always kids who were nonverbal. When I really thought about it-she was just trying to get them to interact with her. With verbal kids, she normally played very well.
2) Some kids "feel things with their mouths." Biting isn't really any worse than any other normal (but unacceptable) behavior-it's just that adults tend to react so dramatically to it, since we associate the behavior with animals. She shouldn't be kicked out of daycare for this anymore than she should for pushing, having a tantrum, whatever. Your daycare should work with you to address the issue, not "get rid of the kid!"
3) Choose a response method and stick with it. Be VERY consistent. I know too late that what I should have done-every time-is calmly tell my child "no biting," and immediately leave the park or wherever we were. Instead, I tried reasoning with her (because she was extremely verbal), time outs, etc.-and what this was doing was giving her too much attention for the behavior. In truth I sometimes didn't want to leave wherever we were because it was inconvenient, but that was exactly what my daughter needed me to do. Find out what your daughter is trying to tell you.
It WILL end. My 4-year old today is a sweet, empathetic, gentle child. Back then I might have thought she'd end up an aggressive "monster." Feel free to email me; I have more suggestions if you don't find something that works.