You can partition a Fusion Drive. The limitation is only one partition and it must be on the HDD.
I have read reports of people booting Windows using external drives and Winclone. Boot Camp will not install on an external, so getting the windows image on the external would be the trick.
I guess it depends on the image. I've found some win images need a quick repair from DVD to fix the Master Boot Record or such and that probably won't work on a TB drive. I'm going to try do do without bootcamp and just rely on Vmware for now.