Investment, Hmmm?
If your friend is planning on producing market quality grapes, then he'll be using a high spray program, heavy on fungicides but also insecticides at times. I doubt that you would be able to keep up with moving the hives as often as necessary to prevent accidental poisoning of your bees.
I don't think bees are a major pollinator for grapes anyway (at least not what i have observed on my grapes). Maybe contact your local extension office.