TransTech few days ago released a transformation pack for N900. What it does, it only changes look and feel of N900. Here is a quota from the article.
Finally, after about 15 to 20 days of hardwork in my spare time (edit: and further 8 days of typing the guide), I have something really beautiful thing to give to my most loved community.Video and Apps that are Required after the break.
So this (Project) is called MaeMeeMo i.e. Its a mixture of Maemo5, Meego (Harmattan) and Nemo. As you all can see in the screenshots and the Intro Image (below), it has the goodness of Maemo5 (Homescreens), Meego (Harmattan) standby screen as lockscreen, and Nemo look and feel.
THIS is NOT an APP, its a transformation pack which requires some resources like themes, transitions, icons, depending apps and plugins. etc.