I don't want to compile shared project to any kind of library. I just want to use existing classes like they would integral part of client project.
I want to edit/develop/improve the shared project from any client project that use it.
I've ran trough google, but couldn't find the simpliest/more convenient approach.
More simple:
I want drag and drop shared code project, and be able to edit it anywhere. How?
There are two options: Use a static library, or include the source files directly in your project.
If you don't want to use a static library (which IMHO is the preferred method for iOS and integrates well with Xcode), you could just add references to the shared classes either as file references or as a folder reference.
Either way, the build toolchain will link everything together into one Mach-O binary, which is the only way to deliver code for the iOS.