You can definitively get a CMake-driven unreal project. In 4.5 preview, Unreal Engine Linux build process ‘natively’ generates a CMake file (and makefile so) which could serve as input to build the whole engine in whatever IDE you want (I build UE4Editor from QtCreator).
It is generated by the command
mono Binaries/DotNET/UnrealBuildTool.exe -makefile
from the /Engine/Build/BatchFiles/Linux/GenerateProjectFiles.sh script.
I couldn’t say more as I am not so comfortable/haven’t dig enough with UBT yet…
Edit:
Found the command for individual project:
/Engine/Binaries/DotNET/UnrealBuildTool.exe -makefile -project="/your_project_path/your_project.uproject" -game -engine -progress
PS I am on Ubuntu 14.04 
Nevertheless it should be expected to work on Mac platform too. For Windows users… I could not say.