Hybrid Vehicle Conversion Services?

OverkillTASF asks: "My '94 I6 Jeep Grand Cherokee has once again eaten through a transmission... at 105k miles. For one reason or another, this has led me to the following question: Are there any companies/individuals out there who do hybrid vehicle conversions? I'd like to retrofit my Barbie Jeep with the necessary equipment to eek out 5 more MPG, be a little more environmentally friendly, but still allow me to get where I need to go out here in the sticks? Do such after-market conversion services exist?"