Thanks to iohannes Zmoelnig, Dan Wilcox, and Spacechild1, it's now possible to compile Pd as a 64-bit windows native application. I'm hoping this will fix the recent trouble arising from new ASIO devices not showing up in 32-bit Pd versions.
The new one's available on the usual page: http://msp.ucsd.edu/software.html
Beware that (as we've already gone through for Mac and linuz) 32-bit externs won't load into 64-bit Pd - you'll need to make or find 64-bit compiled versions of them.
cheers Miller