Does anyone sell a multi simultaneous user USB 'flash drive' / 'thumbdrive' ?

I am looking for a device that works just like the USB 'thumbdrives'
in that you gain access to it just by plugging it in to your USB port
with out having to go through a network setup/login process.  But this
device would support multiple users at one time.  It would have more
than one connector so that computers that are near each other could
plug into it at the same time.  All the users would share the 4gb (or
whatever size) storage the device offers.  It would be an easy file
sharing device without having to unplug and hand over a USB flash
drive.

Perhaps NAS could be more useful to you?

http://en.wikipedia.org/wiki/Network-attached_storage

A 250 Gb NAS should be cheaper than a 4 Gb USB flash drive, like, for
example, this one:

https://multi.gnt.lt/Pages/brochures/Lacie/ethernetdiskmini_en__.pdf

Hi. I agree with harijs-ga that NAS would be a good solution. But with
this product (instead of the Lacie) you don't need any wires at all.
You chose a 2,5" harddrive at the size you want and install it in the
case -> you got yourself a storrage wich is shared wireless,
supporting both IEEE 802.11g, IEEE 802.11b. The device can furthermore
be used as additional sharing usb-flash-drives via the integrated 2
usb2.0 ports.

There are several "extra-features"- that you can read about here:
http://www.ovislink.com.tw/WMU6000FS.htm

Kind Regards