I think it is possible to add 3rd pneumatic function to extend the boom (like the real unimog). But at this scale it might be tricky to also keep the crane foldable.
I picked a wrong year to become a lego technic fan. We have only 1 medium-to-big proper technic set - 42242. This is the lowest of all time (according to my quick analysis, also i excluded 1:8 cars).