New Fujinon XF 100-400mm F4.5-5.6 R LM OIS WR lens is listed in local camera shops, such as CameraPro or Digital Camera Warehouse at ~$2500 (AUD). DCW also has 11mm and 16mm Macro extension tubes for Fuji X mount (link to Fujifilm mount adapters page). Both are priced at $125. Fujinon XF 1.4x WR teleconverter is also available.
The new Fuji superzoom lens is similar in size to full frame Canon 100-400mm F4.5-5.6L IS II USM lens, but it is 200 grams lighter.
