For the lucky few who have collected the pre-built LDXE or Gnome images...
ICEAffinity is a cool little Windows app which will allow you to tie your QEMU app to a specific CPU core:
Drop the app in the smae directory and add 'iceaffinity 4' to the head of the QEMU command line.
The first argument is a bitmask of available CPUs. '4' tells ICEAffinity to use CPU core number three on my quad core laptop. (1, 2, 4, 8)