I always liked Dakar trucks and was never quite sure how to modify an existing Tamiya semi truck to one. (I've seen others do it, but felt it was beyond my skill set). Then I recently found this one and have ordered it. It's meant for a Tamiya road car chassis, but I have an old Axial SCX that I believe will work for it.
https://www.ebay.com/itm/RALLY-LEGEN...4AAOSw8d5ZU3pQ