Sorry to hear of the accident you dont seem to have a lot of luck with other drivers! just a couple of thoughts have you tried contacting Martin Bennet re a welded stock he always seems to be able to fabricate stuff, or how about finding a trainee marine engineer to do one as a project Im sure the grey funnel line will have some spare alloy knocking about around the Clyde. The wooden stock seems like a good idea does it hold a standard alloy blade? At least a wooden stock will be quick getting you back on the water even if its as an interim measure whilst you source some one to fabricate one in alloy.
Dom