Generally, in many municipalities, you can build anything that is less restrictive in a more restrictive zone. That being said, why would you want to? The value of a property is in its available density and built out density -- the number of units that you can build on a property (multifamily) or the number of rentable square feet that you can build (commercial). The more the better.
Municipalities may differ from each other, even within the same county. So it is important that you check with each municipality's planning department's zoning code and staff to verify the allowable density. There are consultants who specialize in obtaining "entitlements" from municipalities such as approved site plans, zoning changes, utilities, etc. Having one on your team to do the initial research for you will save you much time and money down the road. It is as important to know what not to do as what to do. What you don't know that you don't know will always bite you and cost you more money than paying someone for initial professional research.
Your commercial real estate agent (you are working with an agent aren't you?) can refer you to qualified entitlement consultants.
Lackman Commercial Group
Keller Williams Arizona Commercial Division
Jan 8, 2009