If you've had a search and tracked down Stoppy Stars (they ordered us generic stuff like sprockets and chains in from the US in a week back in 2008) and My Town Moto and the other couple of bike shops and are still having no luck then get someone to DHL bits in.
When we were there we received a DHL package from Melbourne, Australia in 3 days. It contained some bike parts, a guide book and some other random gear. We encountered no customs problems.
As for the drive shaft seal, maybe an industrial supplies place could find you a suitable (though non-genuine) replacement if you get desperate.
Vladivostok - Denmark 2008... Finished.
Denmark - South Africa 2010-2011... Finished.