just because there's no 'official' support for dualbooting meego and/or PR1.3 maemo doesn't mean it will not be a direct possibility. meego will work on the N900 platform, and the community will make it dual bootable (read: make it easy for people who don't feel like reading or putting in the time and effort to do it themselves). look at the direct quote...

to boil it down for you: it runs on the N900. it has to, as it is the development platform for meego on ARM. it won't be officially supported and no official dual boot option will exist for one simple fact: if it is 'officially' released by Nokia, then it will have to be officially SUPPORTED by Nokia. Since this device is at its commercial 'end of life', Nokia cannot be bothered with that. That being said, this community provides excellent support for pretty much everything you need, and will provide the dual boot methods, just like it did for android... or mer... or ubuntu... Just be patient, and actually read.