How far ahead will ATC issue runway crossing clearances at controlled FAA airport?
I suspect that you're thinking of this procedural change that took effect from June 30th, 2010. Before the change, a taxi clearance could indeed allow you to cross multiple runways, but now you can only be cleared to cross one runway at a time:


  This change establishes the requirement that an explicit runway
  crossing clearance be issued for each runway (active/inactive or
  closed) crossing and requires an aircraft/vehicle to have crossed the
  previous runway before another runway crossing clearance may be
  issued. At airports where the taxi route between runway centerlines is
  less than 1,000 feet apart, multiple runway crossings may be issued
  after receiving approval by the Terminal Services Director of
  Operations.


It was a big change at the time (according to what I've read) and it was widely publicized by the FAA and other organizations. The relevant ATC instructions are in the ATC orders 3-7-2:


  Aircraft/vehicles must receive a clearance for each runway their route
  crosses. An aircraft/vehicle must have crossed a previous runway
  before another runway crossing clearance may be issued.


The orders have several examples and the corresponding phraseology.