In the "real world", similar wares (commodities) from different cultures may be valued differently, but when one considers inter-tribal trading in Widelands and game dynamics, should we impose those real world variables between tribes?
If, for example, an ingot of Atlantean gold has a different value than an ingot of Barbarian gold, then I would say they SHOULD look different. If, however, gold (or any other ware) trades at par between tribes, then IMHO I think they should look the SAME to mitigate confusion, and the extra space required for more complex code and additional graphics, assuming we may some day be able to draw from a single library images that are common between tribes. (in the spirit of Bug Report #536578, Bug Report #672248, and Bug Report #672251) hint...hint
Until I can be convinced of the need, I vote for using the same image for all tribes to depict a ware that is common to them.
KISS - (Keep It Simple... Surely)
I see little people.