I never owned an N800, but it most probably uses the Mass Storage specification for USB.
If you're torrenting directly to the N800 (and running the apps off the N800), I can't see any reason why this would fail.

The N800, afaik, has USB OTG, so you can connect an HDD to it (but you'll need a powered hub or the HDD needs its own power supply).
You'll need a female-female A adapter to do this (many videos on youtube), it can be bought from places like ebay, and it's very cheap.
Not sure if the N800 has internal storage, but it should be able to use fat32.
Open terminal and type mkfs.v then press tab (wherever that is on the N800) to see if it has mkfs.vfat. If it's there I'm sure it supports it.

Hope this helps.