I've heard from a friend that for Asian companies like MediaTek, "going through the front door" is the wrong way to approach them, unless you are a very large and well-established company.
Bunnie also suggests learning enough Chinese to participate in what he terms the "gongkai" (公开), the quasi-open but legally murky design and production ecosystem producing much of our electronics, where documentation and specs are apparently available about as freely as torrented episodes of Game of Thrones.
We have had several customers with issues sourcing this way and not realizing their devices are malfunctioning.
You need to be careful when asking for quotes. If Bob has stock of product, and you ask 3 different brokers for quotes, you've just driven cost of that product up.
That's especially frustrating when three or four sub contractors are requesting quotes for the same part to be used for the same potential job being inquired about by the end customer.
More seriously, you get to know people who can get you the information/components you need --- often on various Chinese forums. The "guanxi" mentality ( http://en.wikipedia.org/wiki/Guanxi ) is very strong in Asia; to get to the company directly takes a lot of incremental "relationship-building".