Following is a summary of the pointers I received in response to my request for more on Valiant's BSP model. Thanks to all who took the time to email me.
Attributions are as shown.
Some email replies were merged so those names don't appear. Repetitions galore, but because the other stuff surrounding the references might be of interest. The author argues that an analagous bridge between software and hardware is required for parallel computation if that is to become as widely used. Suppose that initially the nodes contain one packet each addressed to distinct nodes of the cube. No other communication between the nodes takes place.