we will only know if the n900 can handle maemo 6 once its released, its as simple as that. even if its possible for the device to use it, as to whether there will be an easy way to upgrade, and if the n900 could run it at an acceptable speed is debatable for now.

the n900 may not be the most powerful device, but its operating system maemo 5 does have some problems such as the lack of screen v-synch, jerky frame rates with video recording, which should be corrected.. even some minor issues such as not being able to jump straight to your photos after clicking on the photos folder is slightly annoying, lol (it always shows all images in my phone, and I have to click on "filter by folder" and then "default camera folder" every single time).

since these issues have been noted as not going to be fixed- for a phone that hasnt been on the market for very long at all, and with its current price, I wouldve expected more support. if the phone isnt upgradable to version 6, i would think optional major maemo 5 updates (available via the built in update service, providing you have backed up your photos and contact list etc) would no doubt be appreciated by many. the wiki does state:- "Since Diablo (Maemo 4.1), Maemo supports "Seamless Software Update" (SSU), which allows incremental operating system upgrades "over the air" using apt without the need for a full flash with every update." ...so I dont see why major all-in-one update of maemo 5 could not be possible in future