Dh says it is really easy, that they used to do it in South America when he lived there, but cannot remember exactly how to do it.

Anyone know?

From www.vegweb.com
I have not personally tried this recipe

Rice Milk

Ingredients:

4 cups hot/warm water
1 cup cooked rice (I've used white or brown)
1 tsp vanilla
Directions:

Place all ingredients in a blender until smooth. Let the milk set for about 30 minutes, then without shaking pour the milk into another container ( i use an old honey jar) leaving most of the sediment in the first container. This makes about 4 - 4 1/2 cups.

Notes: When I have used cold water and the rice was taken out of the refrigerator, it just doesn't come out that well. I don't know why but its best to use warm water and warm rice (you can nuke it if its leftovers but freshly made is best) I have even let it set longer than 30 minutes (overnight) without it making a difference.