I have recently made a protype log or wood splitter and I thought the guiding system would lend its self to a good forging press which has a great amount of acess to the working area. It also has a lot of torsional strength as the frame post is made from 200x100x9 RHS and the guide plate is 16mm bissalloy 400 which is a wear resistant steel with about 3 times the strength of mild steel. Instead of the head having a blade there could a tool holding socket 

The log splitter has a 4" ram at 3000psi gives 16.8 tons force the pump driven by the Pto gives 80litres/min so about 3sec to extend 20" or 520mm and about 2 sec to retract