Which city? Do you have a picture of what you want to do?

For fast infill, plant shrubs about 50% of the recommended distance and use short-loved perennials like desert marigold between them. Have a spiky yucca coming out of a low-growing ground cover, or short shrubs under a pruned-up large shrub or small tree.

Also, a plant with lacy foliage is less of a problem for plants close to it and under it then a dense one. A lacy desert lavender can have trailing indigo bush right next to it because they occupy different layers.

I'd recommend you try and get a copy of the CD titled Water Wise Landscaping in the Arizona Desert. This is a powerful tool that not only has 600 desert-adapted plants but also a gallery section with examples of plant groupings, garden gates, pathways, front yards, back yards, small space gardens, patios, native gardens, shady gardens, wildflower gardens, entryways, benches and seating walls, etc, etc.

It's available free from most city water conservation offices in the metro Phoenix area. Here's a link to Chandlers web site so you can see the cover. Scroll down about halfway.

Here is a link that might be useful: Water Wise Landsapiang in the Arizona Desert

Also don't forget to take a trip to the Desert Botanical Gardens to see what they've got (plus everything is labeled!). I think the biggest key to achieving a desert look is to group things - if you look at the real desert, you'll see lots of plants grouped together - barrel cacti in the shade of a mesquite, Ocotillo and Rabbitbrush next to each other, desert marigold pretty much everywhere - one plant taking advantage of the shade or protection of the other. I'd also recommend Mielke's Native Plants for Southwestern Landscapes (Amazon link below) and George Brookbank wrote a great treatise on gardening in Arizona called "Desert Gardening" that gives you the nuts and bolts of gardening in this challenging environment. Good Luck!!

Here is a link that might be useful: Mielke's book