Rocket industries in Sydney do a 3 gauge (52mm) panel. But it's made by autometer so expect to pay top dollar. I got a single gauge panel (VDO) from a company called Airco in Sydney, $8.40 inc GST. (the Autometer equivalent was $40) !!??
Didn't enquire about a 3 gauge panel, but if Airco have one, the price should be sweeeet.
http://www.airco.com.au/
Hope this helps.