The 27 is opposite the photo above in that the fuel filter is mounted on the portside of the compartment. I do like the idea of another access hatch though, I will need to take some measurements to see if that is actually an option. As I recall the 27 q-berth does not have the depth, I don't know if a large enough access could be made to be worth the effort. A measuring tape will answer that question though. The exhaust system is also on that side of the compartment so I would have to measure and see how much is blocked.
To answer your other questions, yes, I did check that fuel line and it is tight, the top and sides of the filter are dry so that leaves only the petcock. What I was thinking is that in the process of opening and closing the petcock I may have also loosened it by turning in the threads? It was a difficult little lever to move. On our 2GM I am not aware of any other bleed screws in the fuel system, my manuals are down on the boat so I can check those on Friday as well.