Robert,
I always start with the local or state Apartment Association and check their vendor lists. They often have many contractors and rehab contractors listed who will do property renovations. There may be local contractors, too, who take on this type of large scale project. As others have said, if you can get Purchasing Agreements in place with appliance companies and hardware suppliers, you'll get the best pricing when buying in quantity. As far as removal of old appliances, I always call one of the local re-sale shops first and see if they want and are able to buy any of the old ones. Sometimes they cannot, and when they can't we have them hauled away so that we meet the environmental disposal laws. I do like to use that local shop because they have the ability to inspect and ensure the appliance is in good working order before they put it for sale in their shop. Craigslist is certainly another option, too, but usually no one wants to pay much and then if you have 50 stoves, 50 refrigerators, etc. where do you store them while you wait for someone to buy and pick them up from the property?
For cabinet installs, I recommend using Lowes, etc. and this has worked well for me in the past. (We also used an Amish family that came and measured, created the cabinets, and installed. But that can get pretty pricey if each cabinet is "custom built.")