I haven't seen any manufacturers do it, although I agree that for at least some users if would be very beneficial. In general, the manuals I've used range from numbingly-poor (Sony RM-AV2100 remote comes to mind, although the Rotel 1068's manual was pretty unpleasant as well) to mediocre to pretty darned useful, with the useful ones entirely too rare. Outlaw's manuals have generally been better than average, but on a product as complex as a surround processor there are details (such as explanations of how the logic works in a bass management system) that are typically left out.

An "advanced" manual is a cool idea, even as an addition to the normal manual.