Australian online stores, I believe, stock a far better mix of Australian, Japanese & US designers than overseas stores.
1. Kelani Fabric 2. Amitie Textiles 3. Duckcloth 4. I Just love That Fabric (for oilcloth & blackboard cloth) & 5. Funky Fabrix
There are hundred's of online fabric sellers in the US (including Etsy) and with our aussie dollar so high, purchasing overseas has never been more attractive. I received a comment the other day from an Etsy seller who said she was "constantly amazed at how many orders I receive from Australia, you guys are sewing queens!" So here are just two of the many that I personally use and recommend.
If you are a registered business with an ABN and happy to purchase full bolts of fabric then try these distributors. Many fabrics you need to pre-order months ahead of delivery so you need to be organised. Bolts of fabric are heavy and can be costly to freight. You need to do your sums and work out if it's really work it.
Charles Parsons - Melbourne based, includes designers such as Alexander Henry
Mac Crafts - Located in Sydney and stock Michael Miller (including Paula Prass)
Caprice supply spotlight with many of the basic & homewares fabric
If you are needing large volumes then you have the option of going directly to the US or Japanese wholesaler/distributor/manufacturer.
I've only personally dealt with Michael Millers international wholesale section and they were extremely helpful and efficient. I didn't proceed at the time as the Australian dollar was extremely low so with freight, GST etc, it didn't seem as worthwhile as it would now.