I shipped from Australia to Busan (Korea) in 2008 and then rode up the peninsula to Sokcho before taking the ferry to Zarubino (Vladivostok).
Getting your bike into South Korea is not difficult, you can buy insurance at the dock for the period you wish to ride in South Korea. Only important thing to note is that motorcycles are NOT allowed to ride on freeways in Korea - otherwise you are fine.
To the best of my knowledge, the only other vehicle ferry you can take is from Busan to Shiminoseki in Japan.
There is a ferry from Incheon to Yanchai but I don't believe it is a vehicle ferry, and in any case you wil struggle to obtain import authority for your bike into China.
Shipping to Singapore from Busan or Incheon would be your best bet. However, you will likely have to crate your bike and wait until the next scheduled shipping date. I used Eagle Shipping in Busan to manage the importation of my bike. If you want to PM me I can provide contact details for the ubiquitous Mr Lee.
Garry from Oz - powered by Burgman