We keep the cooked meat in the Cambro, and then once it is ready for serving we have a couple portable food warmers/steam tables like this:
These work good for us since we usually either have access to electricity, or we use our Honda generator. When we do not have access to any electricity we use chafing dishes.
For vending the portable food warmers/steam tables work best when we use the roll top lids. Makes it much easier to open and close 80,000 times day.
Ohhh, and I have seen QN4U use electric roaster ovens.