Who's the arms supplier of last resort for dictators? Not East European gunrunners. China will, it appears, sell to any government. For cash, or raw materials. Thus tyrants in Asia (Burma, North Korea, Iran) and Africa (Sudan, Zimbabwe) can get their orders filled, no matter what the rest the world thinks. China does not, however, appear to service rebel and terrorist movements, at least not directly. These groups do have to find a willing gunrunner to supply weapons, and often deliver them to out-of-the-way places. But the gunrunners can usually manage to buy Chinese arms, especially the excellent AK-47 and RPG clones that China has long manufactured.
China has been using availability of arms sales to get deals for raw materials in African countries with shady reputations. Sudan is a prime example. China supplies weapons and trucks for the military, stuff that has been used to slaughter hundreds of thousands of civilians in Darfur. But in return, China gets lucrative oil deals. China offers diplomatic protection to its clients as well, since China has a veto in the UN Security Council.