Neil,
Two candidates for historical interviews would be Elvan (Al) Roderick and Dave Niswonger.  Both are Dykes Medal winners in their 90s with Al in a Missouri nursing home and Dave in assisted living.  Time is of the essence.
 
During the Des Moines AIS Convention all the presentations were video recorded by, I believe, Jurek.  You might inquire about those with Wayne Messer and the Iowa folks.
 
Jim Morris