I assume the bus tracks referred to are timeline representations of busses, where volume(etc) envelopes can be applied ?
If so, I guess that partially caters to my request for as 'Copy Envelope' function, for instance to apply a uniform fade to a selection of tracks (...?)
You can also apply FX and pan envelopes over the bus tracks, as well as volume. In the long run, this is actually way faster than copying and pasting a bunch of envelopes over all your tracks. Much cleaner and easier to edit too.