I am not sure why you would want to use a command like this but I am sure there is some reason for it, so here ya go;
$ for i in $(seq 1 1000); do let "size = ($RANDOM/100)"; dd if=/dev/urandom \ of=file-$i count=$size 2>/dev/null;done
Maybe if you want to prank your cubemate or something by adding 1000 files to his desktop, it would be useful. Be creative. Let me know the best use for this.