IF I end up doing this, it likely won't be a quick project. This is my DD, so I plan most work so that it doesn't take it offline for commuting. The vehicle is built for use in the back country. The reason that I did the conversion is that I really enjoy driving it, and decided that rather than buying a commuter car and only driving the Jeep occasionally, I'd rather use the same money to do the diesel swap and be able to drive the Jeep all of the time.
Gearing is 3:73 with 31" tires. It's basically geared as high as it can be and still pull the mountain passes at a reasonable speed.
The hybrid thing would really just be a side project for fun to see what can be done to it, so I would have to do it in a way that wouldn't take it out of service. Because of that, the electric motor would definitely be driving the front of the crank. I've been talking with my machinist friend about converting a Honda IMA motor for this use, and it doesn't sound like it's going to be all that difficult for him. Browsing some of the hybrid boards, it seems that all of the work has already been done figuring out how to make this system stand alone, with the exception of the fabrication to make the motor independent, so this would be by far the easiest and likely least expensive route.
Changing the transfer case and drive lines just isn't in the cards right now. Other than the work, expense, and downtime necessary, there would be a lot of packaging challenges. The exhaust on the Kubota has been one of the most difficult parts. The manifold is on the driver's side, just like the Jeep engine, but the Kubota is deeper, not giving enough room to run around the front of the pan to the passenger side like the stock exhaust did. The only possibilities were to run under the pan, causing clearance issues, or run down the driver's side in close proximity with wiring, fuel lines, and the front driveline.
Right now it has a 2.25" exhaust running under the pan, but I'm putting together a ceramic coated 3" exhaust that will run down the driver's side instead. Once that's done, there would be sufficient room on the passenger side for a battery pack on top of the skid plate. I like this layout, and don't really want to tear the whole thing apart again to change everything
I took the rare opportunity to borrow a car, and sent the manifold and turbine housing to be ceramic coated this week. I'm getting them back today, and I'll be reassembling it with the 2.25" exhaust tonight and tomorrow. After that I'll be able to start building the 3" exhaust while the vehicle is in service.