Where do you want to go?
I know Kuoni offer holidays to Beijing and Shanghai as do Hayes and Jarvis. You could also try Virgin Holidays and BA Holidays.

Try China Holidays - they do tours but they will also tailor make a holiday for you. Based in London with good local knowledge of China as their reps go there often.

We're doing a 27 day tour of China in October.

It took me a couple of weeks to cross reference differnt tours offered by different companies, we eventually settled on CTS Horizons' China Panorama.
They do lots of tours of China, take a look at their website:
http://www.ctshorizons.com/china_index.asp?country_id=20&gclid=CKn108SPo5ICFQxC1Aod7XEcQg

But no one offering package holidays that anyone knows of?

You haven't said where in China you want to go so it's a bit hard to advise you any more than we already have.

What exactly do you mean by 'package holiday'?

Although ours IS a tour, we've booked it as a package, so I consider it to be a package holiday, rather than something we've organised independantly i.e. booked hotels, rail travel, flights separately.

Airtours pulled their package beach holidays after it became clear they werent going to sell very well. You could look at maybe getting a tailor made with H&J or the like that includes Hainan Island... I'm presuming you wanted beach with it... In the future they may sell them again.