Plug-in Hybrid Conversion kit

I love my 2007 Mercury Mariner Hybrid, however, I would happilly give up some cargo room or mount the spare tire on the rear hatch to gain the room for additional and more efficiect batteries and a plug-in conversion kit that would mak this stellar vehicle an extened rage vehicle. Something that a good mechanic/auto-electrician could do easily. Perhaps something for the SEMA show.