I won't brag either, but I'm a short ass 6'5" powerhouse with a track sprint racing addiction. I have never ridden any wheel with more than 32 spokes. My everyday track training wheels are 32 spoke Aeroheads and they have never lost true after possibly thousands of standing starts and sprints from speed. I started out riding road and track at 140kg (308lb) and am down to 115kg now. My first road wheelset was 28/28 spoke wheels and after 3 years, one spoke started coming loose so I ventured into the world of wheel maintenance and got a spoke key and a tension meter. I've never broken a spoke, just been lucky to have well built wheels.

As chris points out, fatigue in your spokes due to insufficient spoke tension appears to be your dilemma, and is a very common dilemma for us larger folk. Basically as I understand it, the tension built up in the spoke in the wheel build is what should "unweight" as the wheel rotates. When there's not enough tension, the spoke will fully unweight and move in the spoke hole and cause fatigue and failure at the J-bend.

Now that we know your location, perhaps some nearby people can point you to a good wheelbuilder that can help in your situation. Perhaps even ask around in the road racing and training forums as there may be more knowledge about in those places.