Thanks Mike and Eric for the replies,
I couldn't find new all-metal cans in the US either, but as the cans I need are for display only, the rusty cheap ones will do....bought another one today:
http://www.ebay.com/itm/201537908262
Was at a hobby/home decoration store yesterday and bought a cheap Chinese replica Shell sign for about 5 dollars on sale. It had all the features in the sign embossed in the tin. Cut out the shell carefully with industrial scissors, epoxied it to the can and repainted it.
Thanks. David