And the world is struck with awe!
No really, I have just completed an experimental GCC 4.7 (current SVN trunk) build using mingw-w64 trunk, which through an ingenious patch to libstdc++'s configure contains all goodies needed for a working (simple test case only, as always :) ) std::thread. There is only one rather major caveat: you must link with "-static" or your executable will crash.
Seeing that this is an experimental feature, I didn't see the need to hold back a build like this any longer. It includes a posix-threaded (lib)gcc, which is also something new and upcoming, thanks to Kai's recent great work on winpthreads.
Mac builds refused to work due to http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50229
If there really is demand, I can look into backporting the necessary patches to GCC 4.6.
What does this mean? GCC 4.7 and mingw-w64 will most probably bring you a fully/mostly functional C++11 std::thread!
Enjoy and please report any bugs/problems you may encounter!
PS: Download links: