We drive a pair of metal fence post in the ground at both ends of the row and run wire between them to support the canes. Long rows require a pair or two along the length of the row in addition to those on the ends.
The system you describe should work, too, Submarinesailor. I think I'd drill a hole in either end of the board to run the wire through. New canes tend to come up outside of the support wires. It's easier to capture the new canes if you can take the wires down and restring them fairly easily.