Hi,
when talking computer vision message standards one thing comes to mind, features.
It is not unusual to have different nodes exploiting the same kind of features (think SIFT/SURF etc), so that rather than extracting several time the same features, a single ‘extraction’ node does the job and publishes them. They are in turns exploited by (several?) others. A standard message may not be straightforward and I’m not sure this problem fits the scope of this proposal, however it certainly would be useful.
Cheers.