A longer connecting rod would probably help if the damn piston pin wasn't closer to the BOTTOM of the piston than the TOP!

The piston pin needs to be about half way up to skirt to distribute the load evenly on the skirt.

Also

Moving the piston pin will also require the cylinder to be located higher or lower affecting the crankcase volume. 

One of the tricks in a good engine design is finding the happy medium in all of the design parameters simultaneously.  If you optimize one parameter it often hurts another parameter so bad that the overall power and or reliability suffers.