Michael Abshoff already responded to the ATLAS question. I don't have access to a 64-bit Windows. Given the volume of legacy 32-bit applications where I work, there is no chance of 64-bit Windows access for me for at least 2 years.
Windows 64 actually has a very nice feature: WoW (windows on windows). It can executes any 32 bits software, AFAIK (which does not run in ring 0 of course).
VS2008 with 32-bit windows should not have any problems (as you mentioned on the Wiki page referenced above).
I wish it were true :) I can't build numpy with mingw ATM, because of bugs in mingw. Things like:
What needs to be done to figure out msvc9 support on mingw and how can I help? I am a Windows n00b (mostly by choice) when it comes to platform-specific issues.
Then, I am afraid you won't be of much help, ufortunately.