A few questions. Is 'winter' your rainy season? What is your elevation? I think both of these will factor into how rapidly any fertilizer or organic matter morphs into viable 'soil'.

Because I cold/slow compost, I'll let the hot/fast composters give you their nuts and bolts ideas about how you can prep the black gold you need quickly. But wonder if you can prep one bed and green manure or lasagna the rest of the area, planning ahead for fall planting [2012] That seems less stressful and more doable than so much all at once. [And living with your new micro climate for a while, you will be able to plan better]

Have you posed the same question in the AZ forum? Might connect with someone who has tackled a similar set of circumstances.

Good luck ... :)

Here is a link that might be useful: AZ Garden Forum

I'm on the other side of the world and my conditions are very different.
But...it's also sandy and dry. I put in raised beds when I started gardening, because, well, that's what 'they' said to do. Total pain in the proverbial.
I recommend (unless the caliche means plants can't grow except in raised beds) don't do it. By all means construct edges etc, but do as borderbarb suggests and get layering.
If you raise your beds above the native soil, you could have a real nightmare irrigating them. Just put organic matter on top of the 'dust', and mulch like crazy.

Your soil needs more than just manure. It will also need vegetative waste material to help hold the soluble nutreints from the manure in the soil as well as moisture so the Soil Food Web can use them to feed the plants you want to grow.
Start your soil improvemnet by contacting your county office of the University of Arizona Cooperative Extension
Service about having a good, reliable soil test done so you will know what your soils pH is as well as the levels of major nutrients, which can help guide you in determining how much manure might be needed. Also dig in with these simple soil tests,
1) Structure. From that soil sample put enough of the rest to make a 4 inch level in a clear 1 quart jar, with a tight fitting lid. Fill that jar with water and replace the lid, tightly. Shake the jar vigorously and then let it stand for 24 hours. Your soil will settle out according to soil particle size and weight. For example, a good loam will have about 1-3/4 inch (about 45%) of sand on the bottom. about 1 inch (about 25%) of silt next, about 1 inch (25%) of clay above that, and about 1/4 inch (about 5%) of organic matter on the top.

2) Drainage. Dig a hole 1 foot square and 1 foot deep and fill that with water. After that water drains away refill the hole with more water and time how long it takes that to drain away. Anything less than 2 hours and your soil drainsâ too quickly and needs more organic matter to slow that drainage down. Anything over 6 hours and the soil drains too slowly and needs lots of organic matter to speed it up.

3) Tilth. Take a handful of your slightly damp soil and squeeze it tightly. When the pressure is released the soil should hold together in that clump, but when poked with a finger that clump should fall apart.

4) Smell. What does your soil smell like? A pleasant, rich earthy odor? Putrid, offensive, repugnant odor? The more organic matter in your soil the more active the soil bacteria will be and the nicer your soil will smell.

5) Life. How many earthworms per shovel full were there? 5 or more indicates a pretty healthy soil. Fewer than 5, according to the Natural Resources Conservation Service, indicates a soil that is not healthy.
which can help guide you further.

Here is a link that might be useful: University of Arizona CES

You may want to visit the linked web site, a new gardening program on PBS. Joe Lamp'l has a short book about growing plants that can be downloaded that includes this, "Soil is more than just dirt or a place where roots live. ItâÂÂs the warehouse for nutrients, minerals, oxygen and moisture. ItâÂÂs also habitat to billions of beneficial bacteria that not only improve plant health but fight off disease
organisms as well. Soil is the home for earthworms and nematodes that do beneficial things underground including aerating the soil and adding back nutrient rich castings."

Here is a link that might be useful: Growing a Greener World

Welcome to AZ, Rayduke! I have plenty of free horse manure and will even help you shovel into your truck. No daily wormer or feed through fly poison. I'm in East Mesa if interested.