This bash script will create a vagrant box for you from a valid vmware fusion virtual machine directory. Currently, this is a manual process that is begging for any automation.

make_fusion_box.sh

#!/bin/bash
#
# simple script to create a vagrant.box from a vmware fusion source VM
# andrew_diller@gmail.com July 2013
#

FUSIONTOOL='/Applications/VMware\ Fusion.app/Contents/Library/vmware-vdiskmanager'
METADATAFILE=metadata.json

if [ $# -lt 3 ]
  then
    echo "Not proper arguments"
    echo "useage: make_fusion_box.sh [source vmware vm directory] [target dir for box] [name of box]"
    echo "this script will add the .box to the name"
    echo "sample: make_fusion_box.sh ~/VirtualMachines/myvm ~/vagrant/myboxes vagrant-centos6"
    exit 1
fi


SRC=$1
TRG=$2
NAME=$3

echo ----------------------------------------------------------
echo "Starting parameters:"
echo Source vm dir: $1
echo Target box dir: $2
echo Name: $3


if [ -d "${SRC}" ];
then
  cd $SRC
  echo "- Moved into source directory"
  echo "CURRENT DIR: `pwd`"
else
  echo "Source is not a proper directory, quitting."
  exit 1
fi

if [ -d "${TRG}" ];
then
  echo "Target is a valid directory"
else
  echo "Target is not a proper directory, quitting."
  exit 1
fi

################################################################
# determine if the current dir has vmdk files in it....
any_with_ext () (
    ext="vmdk"
    any=false
    shopt -s nullglob
    for f in *."$ext"; do
        any=true
        break
    done
    echo $any
)

# if we have vmdks, then lets do the thing.
# working with Spaces in names of directory paths is not fun with bash

if $( any_with_ext vmdk ); then
  echo "This looks like a valid vmware virtual machine home..."
  CMD="${FUSIONTOOL} -d ${SRC}/Virtual\ Disk.vmdk"
  echo $CMD
  sh -c "${CMD}"
  echo 'defragged disk'

  CMD="${FUSIONTOOL} -k $SRC/Virtual\ Disk.vmdk"
  echo $CMD
  sh -c "${CMD}"
  echo 'kompressed disk'

  if [ -f $METADATAFILE ];
  then
    echo "File $METADATAFILE exists."
  else
    echo "File $METADATAFILE does not exist, creating"
    cat << _EOF_ > metadata.json
{
  "provider": "vmware_fusion"
}
_EOF_
    echo "Created $METADATAFILE for you"
  fi

  echo --------------------------------------------------------
  echo Creating box....
  tar cvzf $3.box  --exclude="*.log" --exclude="*.lck" ./*
  echo --------------------------------------------------------

  mv $3.box $2
  echo "Moved new box $3 into $2"

else
   echo "This is not a vmware vm directory, bailing..."
   exit 1
fi


echo DONE