Yes it is indeed possible.
I ended up buying the MY13 Maps, and was very happy with the result.
I was also looking in to hacking the maps.
(There is quite a bit of info on hacking these specific maps in the BMW world), so I immediately backed my original maps up, and copied them to a spare SD card,
and started hacking away).
(I am sure backing up the maps constitutes as fair use in my case, as with software/media you can legally make a backup if you hold a license to use the said software / media).
Hacking the map data will probably not be classified as fair use though
The maps on the copied SD card worked, but the Sat Nav was very slow to start, and very slow to update whilst driving around.
Finally, anyone thinking of asking me for a copy of the maps, please DON'T. If I can afford to shell out my hard earned for the map upgrades, then there is no reason why others cannot do the same if they REALLY want the upgrade.