So.. The original Kamikaze was pretty successful with a .65 engine and a .90 engine. I decided to shrink that boat down, add a step to the keel, and use a .29 or .30 engine on a full tuned pipe. I'm not 100% on the step hull just yet, but it looks pretty appealing at this point. Hull size should be 26"L x 14"W x 2.5" thick at thickest part. The step will be 1/2" deep, at the middle of the hull. The rake and keel is tapered from the bow to the transom, so speed should be good. I'm planning on using 9" props, and wet rudder.

Current materials list will include:
Balsa -3/32" balsa sheet, 1/8" balsa sheet, 1/4" balsa sheet, 1/16" x 3/8" balsa strip, 1/8" x 1/4" balsa strip, 1/8" x 3/16" balsa strip
Birch - 1/32" plywood
Maple - .150" 3-ply Maple plywood (55 year old hollow door skin, very nice grain patterns)
Cherry - Various sized strips for color accent.

Rough drawing with the step added to the plans:


Side-view comparison of original Kami ".60 size" to my modified ".30 size"

Top and side view comparison, original Kami and new Kami.