RE: Holding Risotto
In my experience, it won't hold though an entire meal service, simply because of the nature of the rice. It will continuue to absorb the liquid no matter what. If you are doing a buffet, try using half pans, rather than full -- bring it to 75% done, and then finish (with extra stock and cream as lleechef said) and plan on refilling the pan often. Also, the added fat from the cream will help slow liquid absorbtion in the chafing dish. Finally, remember real risotto is a lot looser than most people serve it.
Quality risotto can't be held for an entire meal service if you are doing table service -- you've got to finish it individually, or you'll end up with a pan of glue. I also think your customers would be sorely dissapointed to receive an order of long-held risotto...