Homebrew PCBs

Reading Mike's email on PTH (Re: Markus's machine and old posts) 
conductive ink, I got to wondering.  
I don't think the ink is conductive enough to make reasonable traces in 
it's own right., but is printing a conductive ink onto the surface of 
FR-4 and plating it a way to make PCBs?
My understanding of how it works for PTH is that you hook the un etched, 
but plated, board to either + or - (I don't know which) and the copper 
source plate to the other terminal.  The original copper plating allows 
current to flow either to or from the conductive ink in the hole (as 
well as the rest of the copper), and copper is deposited on the 
conductive ink and the existing copper plate.
This leads me to believe (with no empirical evidence) that the entire 
area to be plated must be electrically connected.  To print a conductive 
ink onto the surface of the FR4 and plate it, all the traces must be 
interconnected.  Is that correct?  
If you can print thin enough lines, you could interconnect with a 
different line width, at the cost of cutting the then plated lines out 
later.
Would it reduce the PS current requirements, since there us so much less 
area to plate?
If a board coated with the ink is resistive enough to run through a 
laser printer and pick up an image, you could print a mask onto the ink 
to shield parts of it from the copper plating solution, and you would 
only plate the traces.  If that worked, you would not have to worry 
about the interconnections, since the ink is conductive enough to 
support the plating, and the entire board is covered by the ink.  After 
the plating, you would strip off the toner and the unplated conductive 
ink in some manner.
Any ideas as to the feasibility?
Richard