Value Added Resellers (VARs) may work if you've got margin to work with. When I ran my company, I'd get emails and calls from random people that wanted support for a product I sold but never purchased from me. If your margin is 5%-10% on commodity products, then that type of support does not scale. Adding warranty costs money to replace. You get what you pay for and stuff made in China is hit or miss (more miss than hit IMO). So, adding warranty means you have to replace defective parts more often. Again, doesn't scale when you don't have the margin.