Well the Reb Beach cutaway serves no purpose other than extreme whammy dive-bombing - a habit that should not be encouraged in this day and age. Also, it still has a headstock which is not what this thread's all about.
The Steinberger, design is more like it but is still has a rounded, convex bottom to base body contour where as the Ibby's are flatter for two-position playing and in the Strandberg, is amputated entirely so that it is concave in that area. But yes - Steinberger and Mike Rutherford ahead of their time. Reb Beach, a headstock - so very much of its time.