I might be crazy but here goes... I have a 1.8" Toshiba hard drive (from an ipod) in a tiny 1.8" HDD enclosure. My N800 can power the hard drive and access all the files from it but the cable between the two gets in the way when playing music (and also gets unplugged from time to time). Is there a wireless way (such as bluetooth) to access the external HDD? I understand I would have to power it another way but that won't be a problem. That way I would be able to keep the HDD in my bag/pocket and use the n800 to listen to music.

Failing any suggestions, I am thinking of attaching the enclosure to the back of the n800 (onto the battery cover) and modding the USB connection.

Like I said, ANY suggestions are welcome

This is what you want. Too bad you can't buy them.

At some point in the future you could purchase the EDS WiDrive, or Seagate D.A.V.E.

If you need something now, you could grab something like this:
http://tintuc.no-ip.com/linux/tipps/mgb100/

It doesn't have an internal battery like the WiDrive or DAVE, so you'd have to connect your own battery to it, or plug it in..