Is this what you're after?
http://www.iceinspace.com.au/forum/d...AAAAAAAAAAD//Zhttp://www.iceinspace.com.au/forum/d...AAAAAAAAAAD//ZJust need to work out what thread size & length, and what style knob you like. Elesa & others make them, and they're sold through a number of distributors like D&D Barry (sell Elesa & Ganter Griff) in Sydney, DOTMAR (sell System Plast) in most states, and other crowds. Have a look here
www.elesa.com,
www.ganter-griff.de &
www.systemplast.com
Most likely cheaper than through an astro shop as well.