I simply couldn't go past Millie at Wedding Bunches and Blooms http://www.weddingbunchesandblooms.com.au
I went and got quotes and met with some of the other 'more popular' silk flower suppliers rec'd on WC (including ones mentioned on this thread), and was very disappointed with their service and samples.
Millie was awesome - I was very apprehensive about using someone I would never meet (she was in Adelaide, whilst I was in Brisbane), yet I could not be more impressed. Emails were sent between us very quickly (usually didn't wait more than an hour for a reply), had samples in my hand within 3 days of my inquiry, along with a CD of all her work and price lists. And she does sales every month on different flowers, which is excellent.
The other suppliers I went to quoted me upwards of $200 for what I wanted - Millie charged less than $100, and her product was far superior.
No hesitation in recommending her whatsoever, she is amazing!