Not to dissuade you from doing the conversion - but you can get around the need either temporarily or permanently by building a jack plate and jacking the whole motor up on the transom. I have been inactively looking for a short driveshaft for a couple years, but they arent exactly common. Evinrude.com does have parts available and probably has the drive shaft, but I'd guess it be a few hundred - they arent cheap. I have heard of people taking their motors to machine shops and having a welder cut the driveshaft and weld it back shorter, but that needs to be precise.