Iron and Nickel Whiskers

Yes the whisker idea has always been tossed around as a possible catalyst, especially by DGT. I do think that while surface area is important, the topological character of the surface is important as well. More than likely nucleons require some sort of "trap" to cluster them together (whether magnetic, electrostatic, or something like Storms' nano-crack), that doesn't initiate chemical reactions in the material environment, and the surface area simply allows for higher loading and higher flux to coexist throughout the system.

Rossi's catalyst sintered and caused a meltdown of the reactor in the famous test conducted by Levi group.
George Miiley's Pd reactor has run into catalyst problems, and so have all other gas fed LENR reactors.