I've been using x264 10bit build to encode lossless h264 444 intermediates and ffplay from ffmpeg git can play them. I assume kdenlive will open these, with a kdenlive build that uses ffmpeg 0.8 or when kdenlive stable uses 0.8? If so how will they be handled by tools like Frei0r effects etc, as 10 or 8bit.

8-bit