So.. While reading the first few posts on page 1, I was in the same boat as many of the people on this thread thinking that this was either posted to troll, or a guy hell bent on killing himself.
However, after reading through the entire thread and seeing that he is working towards this being a ten year project to get to 500', I'm more understanding of what he wants to do and feel that the comparisons to Doc Deep are a bit out of line. Doc Deep was hell bent on setting a world record in a short period of time and he didn't have the experience or knowledge behind him to do it safely. In contrast, this guy is hoping to go to less than half the depth that DD was shooting for and plans to spend close to a decade building up the knowledge, skills and experience in order to get there. These are HUGELY different scenarios.
Honestly, I think that if someone were to approach this seriously and spend several years of training, learning, and gaining significant experience one of two outcomes is likely to happen:
1. He'll gain an appreciation of the risks involved and maybe recognize that a personal depth record isn't really necessary.
2. He'll gain enough experience and skill to be able to pull off a 500' without much incident.
Either case, the journey would really be the important element here, not necessarily the final outcome.