Traditionally Rugby League International teams are named after an animal synonymous with the relevant nation e.g. Kangaroos, Kiwi's, Kumuls etc (although its not written in stone)
The Mustangs I believe is a great name as the Mustang has an image of a wild, fast animal. It is synonymous with North America and you also have the added "power" imagery of the car!
Its not often I post on here, mainly because of some of the style of postings, this thread being a classic example- " these are all rubbish". No explanation, no alternative no narrative to the reasoning.
For the record the original USA Rugby League Team took the name "The All-Stars". Great book on the subject No Helmet's Required.