I think there'd be value to have a sub-command which, when given a layer path and recipe name, writes out an empty bbappend (if one doesn't already exist), and then prints the path to the bbappend in that layer. It'd be a real time saver when making changes that recipetool can't assist with at the moment, no need to mkdir the leading paths and check the recipe filename to determine what to name the append.
Moving to Paul, but didn't you say you'd implement this Chris? :)
Most likely, just created the bug for tracking purposes or in case I don't get to it :)
Patch sent to the oe-core list for review.
Implementation merged to master - thanks Chris! http://git.yoctoproject.org/cgit/cgit.cgi/poky/commit/?id=d18612a8a96b446ee4a041a2b42577eb5beb6cf8