Homebrew PCBs

Hi,

I was wondering if anyone makes copper covered perfboard for etching. 
Basically, just a copper covered board that's been pre-drilled. 
Searching on google I can find regular perfboard, perfboard with etched 
pads, perfboard with etched strips, but no perfboard with an intact 
copper coating.

It seems like this would be the ultimate rapid prototyping kit using 
toner transfer, especially if you were only using through-hole 
components.  Just etch and start soldering your components in!  No 
drilling.  For SMD, just send all your vias to a pre-existing hole.

I can't be the only person to have thought of this, so are there some 
drawbacks to this I'm not aware of?  Does anyone know of a supplier for 
such a board?  Is there some problem using PCB software with a board 
with predrilled holes?

Cheers,
Don