He initially thought the best approach would be to add recognition of trailing if, unless constructs and appropriate indentation,... but after further investigation thinks that this is too complex to do.

Steve's suggestion is to use brackets to create a container and have -i=4 -ci=2, which is exactly what sauoq has suggested. I think I will go with this mod to PBP - it breaks the recommendation to remove redundent brackets, and changes the appearance of continuation indented code, but seems to better achieve the goal of clear code layout.