I don't have specific guidance here, but a good place to start would be the bibliographies of many of the Chinese history texts in the list. Several of them source from Chinese-language sources. Off the top of my head, Jonathan Spence writes almost entirely from Chinese-language sources. I'm also reading through The Troubled Empire, by Timothy Brook, and I've noticed quite a lot of Chinese authors in his bibliography.

Have you looked already, and if so where and what have you found? If you're in either China or Taiwan, I can tell you where to go to find the good books. In Taiwan you want to check out Eslite, which despite being a chain store actually has a good selection for history and you can find things on pretty narrow topics if you look. In Shanghai on Fuzhou Road near the Old City there's a book shop called 上海古籍书店 that has an excellent selection on the classics, and is also just down the road from 上海书城. I'm telling you book stores and not books because you haven't said the kind of topics you're interested in, but if you are able to get to one of these stores you'll be able to see for yourself what's there.

it might be worthwhile for the sub to compile a list of foreign-language sources to add to the book list

I've often thought about this myself, actually. There are a lot of good books out there. I'm just not sure how many of the regular users here have the required language ability.