Digital BW, The Print

You could produce the fake border effect using film. 

You'd prepare a sheet film holder with an opaque, roughly rectangular
mask with rounded/uneven edges, use it to make various exposures to
get film totally black in the exposed central area, surrounded by
feathered or rough clear edges (eg perhaps 1/4"-1/2" wide all around
on 4X5 sheet film). 

You'd contact those sheets onto additional positive film sheets, the
edges of which you'd abuse with temperature (eg hot, or hot then cold
water, or burn with a light bulb or steam iron). The contacted film
would have clear center where the original was totally opaque, the
surrounding area would be blistered/bubbled, maybe even browned. 

You'd want to produce a bunch of different positives (clear centers)
so the fake wouldn't be too repetitive.  

Kodalith would be ideal if you cold find it, since it's got a thin,
maximum-clear base.

Polaroid Type 51 might be more convenient, if you could find it and if
it wasn't fogged with age.
 

   I have used the external edge effects in the past (using 
> Photographic Edges 6) but have not been able to figure out the
internal edge effect.  (I hope 
> this makes sense.)  I was thinking of getting some old plate scans
but have no idea where to 
> find some.