In Melbourne preferably
Vintage in Sydney have them for Beetle, Type 3 n Kombis best quality available 02-9789-1777
I took a sample of the Kombi channel to Bill Thompson Rubbers in Ringwood and was able to select a match from the dozen or so types they had there.
Raf
Make sure you get one with a metal insert in it as they hold the shape better. There some cheap flexiable stuff around but its utter crap.
Oh and dont bend the metal backed one, until your ready to fit into the door as once bent, it stays that way and it wont fit correctly.
Thanks all, I actually need it for the 356 so will need to buy it by the metre then cut it to size
Bill Thompson is no go, what he has is larger than what I want 
I think you will find its the same size as a VW
Raf
Try Peter Hardt on 03-5977 3556. He restores 356's and sources all the rubbers and felts you'll need.
I bought a rubber kit off him for my 356. Top Quality
Steve