Update: Think I have found a worthy successor, the Motorola Droid 3:

http://www.phonearena.com/phones/Mot...DROID-3_id5305

Mostly the specs far exceed the N900s, apart from internal storage at only 16GB. BUT there's a big fat catch: The bootloader is locked.

Motorola has promised to unlock future bootloaders, maybe we'll hit pay dirt with the Droid 4.