I'm looking for a "digital dictaphone in the shape of a pen that can
transmit files to another computer without docking ie. wireless,
Bluetooth or IR".

The intent is that this device can be used for wireless data entry to
a tablet PC without requiring the user (a doctor) to speak into the
tablet. Input should happen in real-time rather than recording input
to be played back; the intent is that a transcription of the doctor's
words be entered into the Tablet PC as he speaks. Ideally, this should
not require any external modifications to the Tablet PC (a NEC Versa
LitePad tablet with built-in 802.11 support, but no other methods for
wireless input).

Multiple tablets will be in use within the same area, so crosstalk
between the devices is unacceptable.

Are there any products available that meet this description, or
otherwise are usable in the given context (ie. no fiddling with cables
or a larger-than-pen-sized mic, or holding the tablet to face level
for its built-in microphone to work)?