Well, I'm a gadget freak, and could easily see doing it your way. However, one of the beauties of drip, is its versitiliy and adaptibility. I plan zones by the watering needs of plants, the type of emitters being used, and by the total volume required.
Once you have established your flow rate, then plan a system using no more than 80 % of the maximum capacity per zone. Since drip is really, low volume irrigation, I find i can water relatively large quanities of plants at one time. Most hose bibs in my area (city water)give at least 5 gal/min, or 300 gal/ hour. That means I can safely use #240 1 gal/hour emitters, or 250feet of 0.9 gal/hour spaced @ 12 inch inline emitter line (netafim) - best fed from the middle of the 250 ft or looped. Thats a lot of beds. Your flow may be greater, or less - effecting your design.
I use single emitters (1 gal/hour, drip along 1/4 inch tubing 1/2 gal/hour on either 6 inch or 12 inch spacing. I don't use misters or sprays, as I don't really want the diseases associated with wet foliage, but that is here in the Pacific Northwest, so your area may be different. I do use spray stakes (shrubblers) that have releatively coarse 8 finger srays, well suited for containers. Shrubblers put out much more water than drip emitters, so require a seperate zone. misters would require their own zone, so you could program them for short duration, multiple run times (as in propagation of cuttings). Probably all your misters in the plan could be run off one valve.
Next, put your plants into groups by watering needs. Most veggies benifit by daily watering (depending of location, evapotranspiration rate, and soil texture). Tomatoes in Texas sandy soil, need 2 or 3 watering/24 hrs. to prevent fruit cracking, wheras in Seattle clay once every other day might suffice (I've grown them in both places).
So, once you have figured out the zones by capacity, frequency, and plant needs - you can proceed with your design.
Remember that all 1/2 inch PE tube is not the same inside diameter. Bigger is better. If you have capacity to set you maximum flow above 5 GPM, you might consider larger (3/4 inch PE tube as it can carry more water - almost twice a much-assuming you have the capacity from your water source.
When buying valves, this sites sponsor,
www.sprinklerwarehouse.com sells Rainbird and DIG valves designed for low pressure/flow systems. Rainbird makes a valve, pressure reducer (30 PSI) and filter (200 mesh- for those misters) which is compact enough to fit within a standard valvebox. Personally, I use the Weathermatic silver bullet valve with the combined Rainbird PR/filter combo.
Filtration is the key in drip.
30 PSI is better if using large zones.
You can put individual flow shut off valves (mechanical) on each raised bed, which allows you to turn it off and still water other beds in your quater circle. Usefull when leavin a bed fallow, or between seasons.
All drip is easy to adapt to expansion. Just build the capacity into the flow available per zone.
FYI, I have a seperate zone for container plants. It serves plants in front and back of my house, and even serves to water the hanging baskets. I have my container grown tomatoes on a different zone than my inground ones. I fertigate, so veggies and garden flower and shrubs are on seperate zones. Have 14 zones for my acre yard. 3 are turf, rest are drip.
Hope that helps. If more info is needed, write back. Jeff