I had to laugh when I read your example with the dog and the ball because that's the very first thing that always pops into my head too, whenever someone asks me about the word "fetch". Isn't it amazing how strong that association is?
In my neck of the woods, I rarely hear (i.e. in spoken English) people use the word "fetch" in any other context -- not even in the "gofer" one.
However, there is one more context that pops up often enough to mention, I think. People sometimes talk about the price something will fetch when it is sold.
For whatever reason, the use of the word "fetch" appears to be much more commonly used in written English than in everyday spoken American English. Do you have any thoughts on that?