After thinking about Eduardo Martínez's question here: How to know the currency of a field?
I have a suggestion:
Update smarty function sugar_currency_format to have a parameter to specify ISO4217 vs symbol thus displaying
"$123.00" or "123.00 USD" based on that parameter.
This is particularly useful for companies working with multiple currencies with the same symbol, like USD and AUD and quoting in multiple currencies.
FrancescaS