The program does not support this (according to the info and man pages). You best bet is to move the files after they are created. Your next best bet is to add this feature and mail a patch to the current maintainer.
The first option is really not that hard to do and should not be very slow unless you are on a network mounted share. Consider using a fake reiserfs partition for this:
dd if=/dev/zero of=folders.reserfs bs=1M seek=5000 count=0 losetup /dev/loop7 folders.reserfs cfdisk /dev/loop7 # (make 1 primary partition) mkreiserfs /dev/loop7 mkdir folders sudo mount /dev/loop7 folders/ -o loop cd folders $ time echo // |tr ' ' '\n' | xargs -L 10000 mkdir -p time: Real 1m28.2s User 0m9.9s System 1m12.0s
move the files with something like (probably wiser to move as many files as possible at once and not 1 by 1 - use wildcards and xargs -L):
for i in x*; do echo mv $i $/$ ;done