I'm running pdfcrop (version 1.31) on Mac OSX. From what I read on pdfcrop page I should be able to rescale the size of the final document. The suggested approach is
pdfcrop infile.pdf letter outfile.pdf
to rescale the final version to fit to letter. When I try this I get the errror
PDFCROP 1.31, 2010/09/17 - Copyright (c) 2002-2010 by Heiko Oberdiek. !!! Error: Too many files!
Many people are posting nicely cropped snippets of their final results. My cropped material pales.