The nonexistence thing was an error of judgment. In retrospect, it originated in an unconscious assumption I was making that there must be some ground to reality, a kind of "bottom level" of which everything else is epiphenomenal. A materialist might look to quantum fields to fill that role, but when I rejected all my former beliefs, that included my belief in an external reality independent of perception. So all I was left with was thought and sensory experience, and as they were interdependently defined, rather than any one aspect taking ontological primacy, I concluded that they - and hence I - must not exist. There are any number of holes in this argument, but that's how I was thinking at the time.

Unfortunately I'm not yet at the point where I have papers published. For the most part the ideas that come to me in peak states are not specific, easily formalizable facts. In some cases they are directives to do certain things (like the bike trip mentioned in my original post); in other cases, they give a broad direction to my studies. The Tegmark vision is one example: higher category theory seems like it could furnish me with the tools to formally analyze the mathematical universe (or parts thereof) as a topological space; but since my knowledge of category theory is rather patchy, for now I'm simply working on learning some more of the prerequisites (I just finished a course in algebraic topology).

Two cases spring to mind, however, of fairly specific and well-polished ideas that have come from peak experiences. One was a metric on the space of events over a given probability space; it popped into my head as I was waking from a dream during the peak of my mania. If you're interested: for events A and B, we can define d(A,B)=1-P(A|B)P(B|A). You can check that it satisfies the properties of a metric [EDIT: This doesn't actually work, as Sniffnoy pointed out below]; couldn't say for sure whether it's useful for anything, since I got swine flu shortly after that, at which point it got shelved with the rest of the stuff I'd been working on. A more promising example happened quite recently: it was a game theoretic analysis of the relationship between government and citizen which, as I mentioned, might end up as another post here - probably in the discussion area. If you'd be interested to see it, that'd be all the more reason to write it.