UiList with treeView in Panel

Hello
I want to make something like UiList but with tree view.
I see two solutions for that, First is to make new Space in source codes

And second is this hack https://www.youtube.com/watch?v=mRiTfLpRlRU but this is outdated for 2.7ver for that i contact developers on IRC #blendercoderes and Severin(thank to him) fix some errors in diff path from prevision link but there is RNA creating error again.
This is Severin diff path http://www.pasteall.org/54846/diff if someone can help me with this i’d be realy grateful.

Please give me your opinion for this subject.Which is the best way to create that treeview?
For me the second solution is more acceptable because need to change just few lines in source than first solution where i need to add whole new project to blender solution.