Yes - it is in the latest version of IRender nXt.
We are still waiting for some client feedback - e.g. what additional lights or mirrors they would like.
The trees are useful even without IRender nXt, since they make 2D trees with shadows in SketchUp, You can try the trees here:
IRender Ready Trees
http://sketchup.google.com/3dwarehouse/download?mid=9f5aa31dc3ee00ef6c134b68c36309b4&rtyp=st&ctyp=other&ts=1348625380000
Also, Rich has added the .exe to convert the 3D warehouse models to SU 6 or SU7 (as needed). (I see in another thread that some people are converting to SU 8 just so they can still use many SU8 only 3D Warehouse models)
Also, we are adding the same 3D Warehouse browsing feature to SpaceDesign, for use by people who want to make it easy for people to download other collections into SketchUp.