iPhone, iPad and Blackberry emulator for Windows
Do you know of any other os that could be virtualized in a computer using applications like virtualbox and vmware player? Like this one from howtogeek:
And also this
If you're interested in the N900, try Scratchbox, it is meant as a SDK but it contains the environment too. I think you can even find it as a package in the Ubuntu repositories.
Just remember that you won't be able to judge the usability and the speed of any OS this way, and when you're on the road, these may count more than functionality.