Gazza,
They are likely a Nikasil coated bore so cannot be re-bored and need to be re-sleeved. About $600 per cylinder. If the small ends are rusted then I would say the crank is rooted as at minimum the small end journals are water damaged and not able to be linished out. I just bought a crank for a 2 cyl 760cc waveblaster I am rebuilding which retails to the public at about $700. Not sure of your crank cost but I could find out. Its sounding like a lost cause Gazza but you do seem to get into a few of these type lost causes given your posts over the last say 8 years!!