Ok here's another thing worth checking out.
Google Stirling Engine or look it up on YouTube , engine uses heat for fuel I wonder if a guy could figure a way to make a wood boiler/Stirling Engine powered log splitter?
Yup, stirling engines have been around for a long time.
Power to weight ratios makes it hard to beat a good turbo charged diesel though, if you want ultimate power to weight horsepower go with a turbine.
Just dropped a $4800 dollar reman deutz diesel in the skid steer so I think i'll pass on a stirling powered one.