External Firewire HD hotswap between Mac/PC?
 

It's my understanding that a PC with the right software can see the Mac's firewire output as a digital video device via the capture program.
Correct me if I am wrong but would it not be possible to simply "print to" the PC's capture program from the FCP timeline with the finished DV file?

Apologies if this sounds ridiculous.

I would say format on a PC using FAT32 filesystem.
Make sure that you set the cluster size to the largest possible value (64K, I think). This makes a big difference when writing large files. I don't think many standard PC formatting utilities support setting large cluster sizes. You may need to use a program like Partition Magic for that.

Why not AC3 for audio? LPCM audio is very space-hungry; DVD doesn't allow for that.