Violent Temper Tantrums

My 5, almost 6 year old daughter has violent temper tantrums: biting, kicking, hitting, shouting and screaming hateful things, spitting, throwing things. This happens if she is asked to do something she doesn't want to. The tantrums can last up to 2 hours before she exhausts herself. Very intelligent but will not sit down to work on anything unless it is in her terms, in fact that is what usually kicks everything off - having to work or being told to do a job. For example, tidying up toys, homework etc. afterwards (and sometimes mid way through, before staring up again immediately) she is very upset at herself, recognises that she is doing something wrong. Cries at her behaviour and is very remorseful but as I said that doesn't stop her from starting up again full-force. She will try to use a sweet voice to ask for things and change the subject, when that doesn't work she goes wild again. She will also change what the tantrum from what it started as. For example if she has been asked to tidy up and kicks off, she will start hitting etc. then she will be sent to time-out where she will refuse to stay because she will start saying she is hungry and starving and I am the most horrible mum in the world because I will not feed her. Then she is tantruming about being hungry and 'starving to death' when what it was originally about was that she would not tidy up her toys or do her reading. She has lots of energy and 'life'. Extremely deep sleeper, thrashing around, falls out of bed every night, often shouts out in her sleep. Dribbles, sleeps late in the morning, sleeps 13+ hours per night. Good appetite, not fussy eater at all. Very muscular, physically very capable, can run around in the woods happily for hours, lots of energy, doesn't tire easily. Natural leader in a group. Very intelligent, very competitive, stomps and sulks if she loses at anything. At other times is utterly charming, very loving, helpful, happy, kind and fun but if she does not get her own way, she becomes out of control.