At least in Argentina, as you already know, it's called Seven up.
Sprite is also pronounced the very same way as in English. The same bartender will also have some trouble trying to serve you a Sprite if you told him that you wanted a Sprite as it would sound in natural Spanish. If Sprite wasn't a well known brand but a common word, it would have surely already been naturalized as Sprait.
Fútbol for example, is a naturalized word, that has its root in the English word football, but was transformed in such a way that when pronounced it keeps the original sound of its English root.
Cederrón is another example of a naturalization of another English term, or in this case acronym, CD-ROM, that sounds almost the same as the original term in its original language. The only difference would be the ending n, that I guess was transformed from an m to avoid the word ending in m which is an unnatural ending in Spanish.