Homebrew PCBs

Alright, call me crazy, but an idea just occurred to me, and I can't see why 
it can't work.  To me, the most difficult (expensive, complicated, 
unreliable, etc) part of creating a PCB is getting the pattern laid out on 
the board so it can be exposed, etc.  The rest is science ... standard 
procedure, standards times, standard results.  Yes, laying out the pattern 
can be science, but at a higher price, and still takes time to line up the 
image transparencies, etc.

So this idea just randomly came to me ... why not use a projector to project 
the image on the board.  Use a positive-coated board and an XGA LCD 
projector, with a UV bulb instead of the usual bulb.  I get quite good 
results at 300dpi, so if we go with a projector resolution of 1024x768 for 
now, that's about 3.4" x 2.5".  There may need to be some optical 
manipulation done to get it to focus clearly at that distance, and a bunch of 
other little things sorted out (such as calibration for 
non-linear/inconsistent pixel spread), but I can't see why it can't work.  
No, it's not cheap, but I believe it would be really fast, going from 
computer straight to PCB.

Maybe this has been thought of or done already?  Or maybe I'm going off the 
deep end?

Cheers,
-Neil.