John Lucas III is currently a free agent and looking for a job. He's about the same size as Diener but he's a good shooter and has played well when given minutes with Houston. He got squeezed out after they got Mike James and Francis in the off season.
I'd love to get Luther Head. He's not much of a PG but he is a good shooter and scrappy defender. He'd be perfect for this offense. The Rockets will want Ike Diogu though because it was rumored that they and the Pacers had a deal in place before the draft to swap Ike for Head and the 26th pick if Morris Almond was still available. Almond was selected by Utah before that pick and killed the deal.