Ok, update to my previous post. This evening I got the joy of dealing with a new install of City Nav NA 2012. I purchased this 276 from a member here and sadly the CD he sent did not match the product key he sent, no joy from Garmin. So I had to purchase a new CD and key.
What should of been a fairly simple install, online hardware and key registration turned into a... almost all night circle jerk. Will leave it at that for the frustration of dealing with Garmin's tracking and registration system especially if you have several bits of hardware and software keys. In the end I was forced to delete all previous installs, 1998, 2011 and now this new 2012 install.
Finally got everything installed on the 276 and registered. I went ahead and installed the entire 2012 North America mapset from South America to Alaska including Canada. The entire insall took up about 1.25 gigabytes and is fully accessible from my 276. One trouble I see so far is this install nuked the card clean before installing so not too sure the ability to add topo or anything else at this point. I will try and play with it a bit more this weekend and see what I end up with. So, just having the ability to install all of NT NA on one card is pretty cool and would take at least three 512 meg Garmin cards to accomplish this same feat. I am pretty happy with the memory and what it cost, the quality of the PCB and the fact I really need nothing else at this point.
'09 Husqvarna TE610
'12 Tiger Explorer Graphite