Andi - I have a 5 yr old who still gets in about 11pm everynight. TBH we've been through all sorts of not sleeping and I have had to come to peace with it as she has gotten quite stressed about it. I so understand how exhausted and tired you must be but I would tread really carefully about mentioning it too much - has caused no end of upset and anxiety, especially from well meaning helpers. Just my experience and I do realise you are at a crisis point.
We got a cheapo king sized bed and that has helped heaps just from sheer size of sleeping space. Good luck I really hope you do better at finding a solution than we have so far.