Look at this new Artic Cat Wildcat Trail. A narrow, 50" wide, side by side 4x4 with a 700cc parallel twin motor. It is $11,000. This picture almost looks like what it could look like with a 3 wheel setup. Narrow the cab for a front back seating setup, or maybe go 3 seater with a single in the back. It would lose all that suspension travel and only be front wheel drive.
Actually maybe just buy this thing as is and try and lower and aero it. They already make a sweet armoured belly pan for it.