Good luck!
https://cnsuperwu.en.alibaba.com/
They also gave me the contact for a kitchen and cabinet place - www.aisenfurniture.com They seem to work together, and can pack all windows and cabinets in the same container.
The double glazed windows and doors are very heavy. Shipping them here seems super expensive. Not sure how or when KateG got it shipped for around $2000? After all fees and charges the quotes I got were more than twice that just for some windows and doors. The shipping quote the factory in China gives you is NOT the actual price! There are still lots of fees and charges, GST & Duty added to that once it arrives at the port in Australia.
The best solution I have found till now is getting a whole 20" container shipped to Sydney. We often import products from China via my business. But, never a container before. The importing company I normally use (OOCL) gave me a quote just under $10,000 for importing the container, with all fees and charges(there are many additional "hidden" fees), and transport via side loader truck to a local self storage place that can store a container($250 for 1 month). The shipping place said I can keep the container free of charge for 14 days. So, I will have 14 days to unload the super heavy windows and doors(over 200kg for a 2.4m sliding door apparently).