Eddie TX : "I like to think of Reverb and Delay buses as "servers" or "stores" -- each track that needs it goes and asks for the amount it wants (via the Send), which the bus happily supplies and sends to the master (or other) bus. "

I'm not sure I grasp correctly what you're saying, but it seems to me that you see the instruments as they exist in the final product telling sonar how they want to sound.

Up until now I've thought of the source instruments as driving the mixing process, with us pushing them through the mixing process to the product state.

You seem to be offering the opposite view, with the final instruments pulling what they need through the mixing process until they're happy.

Very interesting. I think I prefer this way of looking at things.

Since both reverb busses and sidechaining were brought up, maybe it's not too off-topic to mention side-chaining a reverb bus. It's a very useful technique, in which you put a side-chainable compressor on the reverb bus and key it off the lead vocal so that the glue 'verb is lowered while the vocalist is singing. This will allow stronger reverb effects without letting them get in the way of lyric intelligibility. 

Yes, Paul, this has been my mind set too.
The buss to me, was simply for grouping, like folders.
Throw on some fx and flow thru to the master and bobs yr uncle.
The new concept for me is the send as a parallel/loop back of a "copy" of the track and how you control the fx thru the send levels. Very flexible.
With this new info about simply using more busses for different send fx, I feel excited about the potential.
Thanks guys, sorry for being so thick.
Once you get it, it seems obvious. 
Bitflipper, the result you mention makes sense, but I'm going to have to think about the setup for a bit I think.
Or maybe just do it and see.
Thanks again.  
Glenn.