Names and Numbers

So I'm sitting at home watching football, when a commercial comes on about Verizon 4G internet. I don't know why, but this got me thinking about numbers and naming conventions. Just as examples, 4G internet and the iPhone 4. How far do you guys think you can use a name followed by a number? Personally, I think something like iPhone 13 or 9G internet sounds ridiculous.

So is there a limit? If so, what is it?

And what other names do you think companies will use for products with numerical suffixes such as the iPhone, wireless internet, Galaxy S series, etc.?