I need a cake recipe (preferably chocolate cake) for a 10 in round 2 in deep single layer cake. Can I use the same recipe for two 8-in cakes?

A 10" round takes 6 cups of batter. Just measure your batter and whatever you have left over bake in a smaller pan or make a few cupcakes.

Here's a guide that Wilton has put out that is very helpful

http://www.wilton.com/cakes/making-cakes/baking-wedding-cake-2-inch-pans.cfm