you can write your tool with Package Map (Data Management). and there is a very good example there to use.
Find and create map packages for all map documents that reside in a
specified folder.
# Author: ESRI
# import system modules
import os
import arcpy
from arcpy import env
# Set environment settings
env.overwriteOutput = True
env.workspace = "C:/arcgis/ArcTutor/Editing"
# Loop through the workspace, find all the mxds and create a map package
using the same name as the mxd
for mxd in arcpy.ListFiles("*.mxd"):
print "Packaging " + mxd
arcpy.PackageMap_management(mxd, os.path.splitext(mxd)[0] + '.mpk', "PRESERVE",
"CONVERT_ARCSDE", "#", "ALL")