If you are not talking about name brand watches, it would be hard going past China to be honest.
I myself purchased a knock off for nothing more than a quality check from a Chinese manufacturer a couple a years ago, and I am still wearing it today.
I got a Bape replica and no one has a clue that it is not genuine, however the reason I got it was because we were also going to buy the same watch without the Bape name from this manufacturer for resale through shops, not online.
They even offered to create the watches with our own logo, and all up at the time they were working out to be around $5.00 a watch landed, with a purchase of 1000 items.
I must admit that I amazed that you would be making any profit selling from bidz on ebay, especially with the shipping.
The places to check out would be liqiudators for closeouts and such, but beware of liquidation brokers as their prices will reflect those on ebay already.
Might even be worth dropping jimmy a line to see if he is dealing in, or can locate a decent shipment for you.