Hi Nick

Apparently we get our beams from Capral. Fortunately for you their head office is in QLD (at least it's the right state)

71 Ashburn Road, Bundamba QLD 4304
PO Box 768, Booval BC QLD 4304
Tel 61 7 3816 7000 Fax 61 7 3816 7111

They will probably only sell a full 6m length but they may have a local distributor who can cut you a length.

The guys in VIC have been rounding the corners (2mm radius) and getting them anodised. But that's all optional. Anodising seems to be cheap these days though.