Just to triple-check that I hadn't made any bad patches to ublas, I ran the test against the trunk and had the same results (failure for MSVC2008SP1 on win32 and win64, MSVC2010beta2, Intel 11.1.060, and success on mingw.... and I tried on 2 different machines)
It looks to me like some weird problems are happening with the sorting/binary search of elements on element access rather than on setting the values. However, after setting a value a flag tells the matrix to re-sort upon next access. But I am having trouble tracking down... any ideas on this?. The new test file that I am attaching gives a little more detail on the tracking down the problem. I am also attaching the output on mingw and intel 11.1.
Also, in case there is some weird compiler setting, I have attached my CMakeCache.txt (CMake 2.8) so you can see my flags if you are curious about this.
Thanks,
Jesse