Cogito had a set of "L" shaped foils but it seems that they didn't have time to test the configuration enough to use in the series.
Yves Parlier's new 60 ft twin rig planing cat also features rudder foils. According to sailinganarchy.com, the boat topped 38 kt during the tests and averaged 30 kts in 8 hours. Unfortunately the article doesn't tell fi there were waves or how big they were.
Rudder foils seem to be a good start for any class.