Paul Almond's site has many philosophically deep articles on theoretical rationality along LessWrongish assumptions, including but not limited to some great atheology, an attempt to solve the problem of arbitrary UTM choice, a possible anthropic explanation why space is 3D, a thorough defense of Occam's Razor, a lot of AI theory that I haven't tried to understand, and an attempt to explain what it means for minds to be implemented (related in approach to this and this).
Another idea along these lines is mentioned in this blog post:
http://blogs.discovermagazine.com/discoblog/2008/08/11/will-the-lhc’s-future-cancel-out-its-past/
"Now two physicists claim in a new study that no matter how hard we try, we may never turn the LHC on at all. The study is authored by Holger Nielsen and Masao Ninomiya, who argue that the very particles the LHC produces will prevent the accelerator from ever being used. Harvard post-doc and CERN collaborator Kevin Black relates their argument to the grandfather paradox—that a particle like the Higgs boson goes back in time and prevents its own birth (i.e. the future changes the events of the present)."
It's not exactly quantum suicide, but a similar effect is claimed to actually reach into the past to cancel out any branch where lots of Higgs bosons are produced, as the LHC arguably will do. The prediction is that the LHC (nor any similarly powerful collider) will never successfully operate at full power, and so far it's coming true!
(Original paper at http://arxiv.org/abs/0802.2991 )