The old Hornby Ringfield motor was very similar to the lima pancakes in performance IMHO. With correct weighting, removal of horrible traction tyres (which involved new wheelsets) and attention to correct back-to-backs, I was able to get a 7 car around the club layout back in the day - but only pulling. Oh and the bogies on the MK3 coaches were heavily modified with brass bearings.
Any decent modern diesel chassis with a central motor, drive shafts and a flywheels could be used as a doner and would definitely be a better option, especially if you are DCC.
Good luck. I look forward to your posts!