Getting vehicles to go one way or the other across the Bay of Bengal seems to be a constant problem on this site.
I believe you can go to China, and even cross China, but it´ll cost more than most of us are capable of or willing to pay. And it can´t be done just like that, it´ll need to be prepared well in advance.
Another problem: for about 20 years now, there do not seem to be any regular international ferries operating in the whole area. Only between the Andaman&Nicobar islands and ports in mainland India. It´s disturbingly close to Thailand - but probably still too far away to either swim, or charter some fishing boat to take you there!
There could be some big freightship, sorry I dont remember the name of the company, that goes from Singapore (or Port Klang in Malaysia?) to Chennai, and its got like a dozen cabins for passengers. Very expensive for bikers, but maybe not so much, when considering how much it would normally cost to freight a car.