Okay - have you tried the disappearing chair routine. Basically you do your normal bedtime routine, and then when you say it's time for bed, instead of leaving the room you just sit in a chair, make no conversation or eye contact, but just sit there until they fall asleep.
We did this with DD fter DS arrived and in total it took a couple of weeks - just accept you're in for the long haul, but with us it worked a treat cos DD was always calm when we were in the room. Every night you move the chair a bit further towards the door, until you are sitting outside - for the last couple of nights my DH was round the corner, out of her eyesight reading the paper and having a beer!
A few nights she even said 'daddy, sit on the green chair now'. We've had to use it once since and it sorted the problem in three days.
May be worth a shot.