OEM usually connotes a brand or brand name, but it actually defines the manufacturer. It's not hard to make OEM for your brand / product, you need to have a manufacturer in China make you the OEM based on your specifications and testing. Any manufacturer in China can do this for you, just tell them you want OEM and they will know what to do. As far as laptops are concerned, Apple's Macbooks are already flourishing in LA. Try Alibaba or any Chinese manufacturing website.
International brands such as Sony, Panasonic, and many others will not give out wholesale to just anyone. But you can visit their authorized agents, distributors, and dealers to get the latest products, sale and wholesale prices that you want.