this may be off topic, as its more of investigating on how to do this.
Options are : PC104 hardware, and its available, but a bit larger than
I want, and also $$$

Zworld stuff.  Still looking into this

PIC based.  Since I like PIC's, this has appeal and could probably make
it pretty small.  What I want to do is capture data as it goes to the printer
and store it to memory (say a flash card or something like that).  Then,
sometime in the night, call up and dump the capture to a host PC so I don't
have to go look thru reams of printouts but can just look for keywords in
the data.  Yes, I know I could setup the output to goto disk rather than
to the printer, but I want to be able to print locally in realtime as well.

And the PC might not be one at night, so just a small stand alone unit is
what I want.

OK...had someone done this.  Is it available commercially now?  I am happy
to buy rather than redesign the thing.