No matter how good your counter pressure bottle filler is, there is still the issue of having to remove it from the bottle and then capping the bottle. Recently I have been frigging around with my CPF design and have taken it about as far as I want to go (well for at least a week or so).
Today I made a PET cap with valve that gets around the capping problem. It screws onto a PET bottle (and stays screwed on until you serve) and on top is a plastic coupling with one way valve. The male part of the coupling connects to the CPBF and plugs into the coupling. After you fill the bottle you just unplug the coupling and badabing.
There is more description at: brewiki: counter pressure filler
Today I made a PET cap with valve that gets around the capping problem. It screws onto a PET bottle (and stays screwed on until you serve) and on top is a plastic coupling with one way valve. The male part of the coupling connects to the CPBF and plugs into the coupling. After you fill the bottle you just unplug the coupling and badabing.

There is more description at: brewiki: counter pressure filler