You could try your local Glazier. They regularly deal with aluminium suppliers like Capral http://www.capral.com.au and others. While they wouldn't have these mouldings on the shelves themselves its likely there could order it in for you from one of there suppliers.

I'd also try your local joiner/cabinet maker. They'd also have suppliers who'd be likely to make this stuff.

Or these guys might have what your after.
http://www.oh-diners.com/divers/edge_molding.htm

I know Capral used to have this stuff as I bought some for one of my machines.
That was back in 2007 and it was in the bargain bin as they were not going to stock it anymore.
You may still be able to get it from them but you will probably have to place a large order.