It's likely something that would be both a response to, and a cause of, increased republican sentiment in the settler colonies. I can't speak to Canada or South Africa, but I think it would be a terrible idea in Australia or New Zealand.
In Australia local peerages were roundly mocked from an early date. The mere suggestion of local titles gave rise to the celebrated phrase 'Bunyip Aristocracy.'
There was a very brief movement to make Victoria's second son Prince Alfred the 'King' or 'Prince' of Australia, but that was supported by a few dozen Melbourne property owners and in any case was abandoned as soon as they actually met him.
The first high point of Australian republican sentiment was in the late 1880s and early 1890s- it's possible that as Federation approaches, some one has the idea of creating some royal Australian titles. This is likely to backfire tremendously.
In our timeline, the first Federal Parliament was opened by the future George V, the Duke of York.
The Bulletin (nationalist, middle class, republican, and the most intellectually influential journal in Australia) described it thusly: 'One day this week George, Duke of Cornwall and York, and various other kinds of dignitary, enters Melbourne in a glittering vehicle, with many flags and much Jingo howling, and opens Parliament. He will do it by reading, or looking on while someone else reads, a speech which he didn't compose, about things he doesn't understand, and then he will go away again - once more among the yells and banners of a devoted people.'
As you can tell from that, the monarchy was popular- but at that time the support was surprisingly shallow, too. The Australasian colonies had a very real sense that they were improving upon Britain in several ways, and one of them was the absence of a class system. Landed property owners were deeply unpopular.
If the Royal Family begins creating ridiculous colonial titles- The Earl of Wollongong, perhaps? Prince of Tasmania?- it's going to go directly against those emerging national identities. It's going to give more ammunition to a perennial republican complaint: 'If she's the Queen of Australia, why doesn't she live here? What does she actually know about the country?'
In short- it's not an idea with a local support base, and will probably harm the monarchy.