Never tried the UNC hack. Might have a bash at that.
The actual restriction is in the Win32 subsystem which has both C string and Unicode versions of API calls. Some API is hooked in via the C API which tends to use TCHAR var[MAX_PATH] as the buffers. It's a royal PITA.
The NT Native API and NTFS don't have such small limits (32k comes to mind).
It's a shame really as NT is a beautiful piece of engineering with a shitty Win32 subsystem thrown on the top.