Does it look something like this photo?Mine has a Jeep type frt end. The nose comes off with 4 rubber holdowns and once off the hydraulic gearbox and motor are right there.
Please post photos when you get a chance. I'd also like to see some details of your sprocket design, you may be very lucky and be able to use some tracks from a snowmobile. That would certainly be easy and effective.The sprockets won't be a problem as they aren't much different from the snowmobiles with involute drive so I should be able to come up with something.