Elizabeth:  you can also use the "array" command in AutoCad, just use
rectangular array of a single line at whatever distance and spacing you
like, then do "array" again in the other direction.  But really, most good
architectural drafting supply houses will carry printed graph paper.  But
your method of making cards is pretty good, better than pasting up.
 
For field use, there is also a mail-order supply house called Fidelity
Graphic Arts Catalog that carries both 8 1/2" x 11" graph (bond) and 8 1/2"
x 11" through 24" x 36" sheets (tracing).  Their toll-free number is
1-800-328-3034.  Lots of other keen stuff in there, too.
 
If you need a huge stock of paper it may be worth your while to check on
having sheets printed for you somewhere, if you really are having an awful
time finding this.  You could also then have the project title pre-printed
on each sheet, or a title block.  You could also take your camera-ready WP
provenance card to a printer and have them print you a stack for probably
less than it takes to print or copy a lot of them at the office.
 
I haven't done a search under "graph paper" on the Internet but that could
be worth a shot, too.
 
Best of luck,
 
Irene Henry (lurking architect)