I've managed to take a look at what is involved in doing this and I'm afraid the short answer is going to be no.
The long answer is that once a name is changed on the map, every other instance where that name is referred to in-game requires it to be identical otherwise there's going to be a lot of confused players. Everything is currently standardised.
There is a single central file that has all location coordinates and their names and it wouldn't be a big job to code up a map label changover at the start of every turn (for MP) or off a game (SP) to handle two different sets of names.
Which is all good.
When I went through the data files I found close on 30 other files where names are referenced in one form or another. Some of these are easy to deal with but many others would require the use of special insertion tags as they are buried in sentences of text. File dealing with stuff like weather, rail conversions, decisions (lots), strategies, FSB locations, airfields, random personality backgrounds, VP locations, AI data, statistic trackers, tooltips and so on would all need to be updated and, in many cases, hand tweaked to handle in-line text.
I suspect once it was done it would prevent MP use due to the amount of processing that would be required at the beginning of each turn, so it would be a SP option only.
None of this is difficult to do code-wise but it's a very time intensive, fiddly, big job. As it would involve touching many different parts of the code base there is also a reasonable risk of unintended consequences. If it all went to plan perhaps a full weekend's work would do it but it could blow out well beyond that in the event of inadvertently breaking something.
Given my current work and family committments that's more time than I have availabe.
Having taken a look at this I'd offer the comment that when I designed and coded up the game I didn't do a very good job of modulising the huge amount of text. If I'd been smarter I would have centralised all location names in one place (which I did but there were way too many exceptions) and made all text easily accessible in external files to facilitate translation into other languages, eg. German.
Live and learn.
Kingdom of Heaven has beautiful artwork on the cards.