I have a relationship with a VERY large domain investment company that owns a lot of expiring domains that have Page Rank and I am trying to get a feel for what these domains are worth?  Assuming the buyer is acquiring a PR domain, with little traffic or inherent value in the domain itself, what would PR 1,2,3,4,5,6 names sell for? 
Below is an example of one month of domains that will be expiring, who would be the logical buyer for this volume of domains on a monthly basis?
PR 6=1
PR 5= 22
PR 4 = 155
PR 3= 685
PR 2 = 1725
PR 1= 2826