I'd still like to see a way to attach a target to a bone
If you're meaning something like a character picking something up, (ie: weapon), and then carrying it around, and then even putting it back down, or throwing it away and picking up something else, or that kind of thing, then the best workaround i've found for that involves using 2 or more identical files or/and identical characters.
Save extra copies of the wip, as you go. The trick is to actually attach the object to the bone in figure mode, and make sure you keep a saved, up to date, identical copy with the figure
without the object attached. (usually the file
without the object attached, is the main 'starting' file, and the eg; 'holding gun' file is the more 'secondary' file.)
Then it's just a matter of rendering the video either with or without the object attached. Takes some thought, and save extra files of each, but definatly works.
But maybe you're meaning something else?