Well, you need some basics about audio & such for some of what you are running through your head.
1. To have a zone of audio you need an audio source, a way to adjust volume, and an amplifier hooked up to some speakers.
2. To have muliple sources available, you need a switcher that can switch those sources.
3. If you want multiple rooms with the SAME source, then you can just use something simple, like a speaker selector.
4. If you want multiple rooms with different shared sources, then you need some sort of matrix switcher.
5. Volume controls are traditionally knobs located in each room of the home. This is not one of the best ways to control volume and retain audio quality though.
6. Adjusting audio volume prior to the amplifier through use of a pre-amp is a much better way to control audio level.
7. A surround receiver is typically designed first and formost to provide surround audio to a single room of your home. They have evolved to include 2 and sometimes 3 (or even 4) rooms total. Depending on the specific receiver, you may find that there is built in amplification for second and third zones, or you may need to buy an external amplifier to power the speakers in the second and third zones.
8. Buying an external amplifier for additional rooms and speakers is typically a wise decision.
9. With DISTRIBUTED AUDIO - You have a number of options, which I have posted on in detail before, but will touch on again.
a. Plug a single CD player into a amplifier then run it out to impedence matching volume controls. Very simple, but when the amp and CD player is on, audio is going to all the rooms hooked up to the CD player. Volume is adjusted individually in each room.
b. MOST COMMON: Use the second zone of a receiver to switch multiple sources (tape, tuner, cd, xm, etc.) and then hook the output into an good amplifier, then to an impedence matching speaker selector. From there, the signal goes to volume controls in each room.
c. Better: Use a mid-level distributed audio system like those from Niles or Sonance which allow you to send up to 6 sources to 6 different rooms in your home. Usually you can buy 2 units and add 6 more rooms (12 total). Most of these have keypads in each room that allow for independent source selection from the room in use. So, when the study is on CD, the master bath can be listening to the radio. These setups cost a fair bit more, but offer a much higher level of flexibility for audio.
d. Top Shelf: Crestron, AMX, Control 4 (?) - These products allow for you to pick and choose which components you want and which amplifiers you want. Crestron (as this is what I actually know) offers a 8 source to 8 separate zones pre-amp that controls volume for up to 8 rooms. It also allows daisy chaining of stereo audio for up to a total of 32 separate zones (4 units). Keypads, or touchpanels in each room control audio. This system allows higher functionality though - including XM station information on touchpanels, auto startup/shutdown of components, control of other devices (TV, HVAC, motorized drapes, security, lighting, etc.) depending on what level of sophistication the home is at. I believe with Myer-Emco we had a 8 room 3 source package that ran about $20,000.00 fully installed (new contruction). Audio sources are shared (up to 8 sources), but a separate amplifier is needed for each room. Something like a Sonance 1230 amp or a Rotel RMB-1048 works well.
10. Things like IR repeaters can be added to any room by having an extra piece of CAT-5 somewhere (usually the wall where the volume control is) in the wall. A IR repeater will allow you to change a source, or control the CD player from the room with the IR repeater in it. So, if you are on the other side of your home and want to switch from the tuner to the CD, then want song 4, you can do it all with the remote instead of walking to the other side of your home to start it up.
Pricing that can't be avoided are the speakers in each room that are needed and you will likely need at least one external amp to run things plus a minimum of one volume control per room. In an 8 zone setup, expect no less than about $250.00 per room. You can work it a little less, but you'd be going with very inexpensive speakers.
In comparison, my setup runs about (MSRP) $1,200.00 per room. For a pair of decent speakers, channel of the Crestron pre-amp, amplification, and keypad in room. It does not include wiring, sources, or Crestron control processor or programming labor.
FYI:
http://www.sonance.com/subs/products.php?category_id=33&option=get_category&thread_one_cat_id=29&thread_one_cat_name=Electronics&thread_two_cat_id=&thread_two_cat_name=
http://www.crestron.com/products/show_products.asp?type=residential&cat=1012