Background:

I have a portable USB drive that I use to make sure I have access to common files whenever at home, work, travel etc for cases when I may not have Internet/Network access of any kind.

There are some cases when I have to work simultaneously on a laptop and a desktop computer, and for those cases I usually have to unplug this USB hard drive and move it between the two.

Question: dual-computer USB drive?

Is there a USB-based solution that would enable me to use this portable drive between two computers simultaneously?

If there is not a USB-based solution, does anyone have alternative suggestions, consistent with the underlying rationale?

Rationale:

Sometimes I have to work on a desktop computer with locked-down networking capabilities (such as at the local photocopy shop) and it can be difficult to get a network configuration that allows dual-computer access without breaking things, or accidentally making my USB drive visible to the entire network.

Basically what I need is a very simply LAN that is guaranteed to work regardless of the rules or constraints set by the network administrator for wherever I happen to be at the time.

See also: http://superuser.com/questions/99274/how-to-connect-two-computers-with-usb