The problem: Drum Rack sends are not available with control surface support. Therefor you wouldn't be able to access them with Push for example, or any other number of control surfaces.
Not sure what you mean by this, because it seems there have been some heavy changes on this front.
For example; in M4l I can now easily access return chains (return_chain is now a child for the drumrack device) as well as the send settings in other chains, for example:
live_set tracks 1 devices 0 chains 0 mixer_device sends 0
I can get the value property and even set it (type float), this affects the send-a amount on the first chain the drumrack.
Needless to say; if I can access it using the API you can also access it using a control surface. Simply MIDI map it and you're done (tried before posting).
Then there's the return chain itself; same applies. Not only can I fully access all the devices in the chain using M4l (and thus MIDI map whatever I like); I can also control the return chain itself (chain send level & volume), example:
live_set tracks 1 devices 0 return_chains 0 mixer_device volume
So when you say you can't access sends using a control surface you're either talking about Live 8 / M4l5 or something completely different. In that case please elaborate.
I wonder if there's a way to insert a device and have it automatically map to a selected send starting at a selected note on the Drum Rack of that track.
This is how I picture it: you'd still have 16 macros, but with two dropdown boxes to chose:
(1) Which send (ie. A/B/C etc,)
(2) Starting note (So the 16 macros map to the sends of the next 16 notes for the chosen send)
Totally unfamiliar with the Covert device you mention I can only theorize about "select the send setting for the pad just being struck".
That's going to be tricky, if not perhaps impossible (can't oversee it while replying).
Thing is; if you dump a sample on, say, C1 and A1 you'll only notice them as chain 0 and 1 in the API. And here's the nasty part: the chain's IO section where all of this is defined (Receive / Play) is unaccessible.
The only thing you do have is the chain mixer device, but all that gives you is volume, panning, sends and the activator (on/off) itself.
Therefor (at first glimpse mind you) I don't see any way to link a chain to a specific note. Unless of course you start naming your chains particulary, but that's obviously not the point here.
Yet without that info I don't see this working out.Edit
...using the new 'DrumPad' class. That should make it doable to at least grab the right pad and then access the right chain with everything attached (sends/receive).