Hi Steve,
I've been having quite a bit of luck using toner transfer with simple
sheets of magazine paper and an iron. All of the boards I've made have
been smaller than what you are talking about, but some have been
reasonably complex with 12mil traces so I don't see why it wouldn't work
for larger boards, especially if you have a laminator.
I've written up my experience
<
http://catmacey.wordpress.com/projects/making-pcbs-with-simple-tools/>
on my web site with lots of photos if you are interested in having a
look.
Regards
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