http://www.delgine.com/
Its licensed for free use even with the free Lite version and can export worlds as b3d. It handles static world but seems like a very interesting choice and thus having your whole world as one mesh for the statics, you only need 1 triangle selector to handle your word
Though You would probably import the base and the terrain seperatley.
That would not be hard though as I believe you just make the terrain, export that then build the buildings on top of that then delete the terrain and export that, as to avoid irrlichts gravity issues.
