Pygmy uses the epoxied-and-taped butt joints with 2-inch wide 4-oz. tape with no problems. In reading your post, I think your problem was not putting tape on the outside. When the "board" is bent, the outside of the bend goes into tension. This is where you want the tape. The tape on the inside goes into compression and is just there for the ride.

The tape on the inside (Pygmy tapes both sides) is to keep the board from breaking when you are carrying it around in the shop. If you only tape one side, and then carry it in your hand with the tape side down, then you have the untaped side in tension and it can easily break. After the boat is built, Pygmy then reinforces the butt joint on the inside with a couple of layers of wide tape.

Pygmy also has a clever way doing the joint that makes the tape/epoxy layer very thin and smooth, giving high strength/low weight/minimum bulge.