I just purchased the Treo 650 from Cingular Blue for only $349.99 plus tax.
I called 1-866-4297-2222 and spoken to a Blue Sales Rep. I told the rep that I wanted to upgrade my phone and I asked them to lookup the old Blue phone list and guess what was listed there "Treo 650". I quickly placed an order with them and I should be receiving the phone by Monday or Tuesday. The only thing that happened was I had to extend my blue contract for another year. Also they didn't even asked me to add a data plan.