Check out GraphPaper, a nifty shareware program from Phillipe Marquis: http://www.marquis-soft.com/

It's basically free forever if all you need is "standard rectangular metric and imperial papers with adjustable margins, sizes, colors, distance between lines and captions. There is no time limitation. If you need other papers than standard rectangular paper, you will have to purchase a license."

I've used it for years for mapping paper for role-playing games. No reason you can't utilize it effectively within the templating system of D*I*Y Planner, of course. Once I get through the hunting season, I believe I'll give it a try! I can think of several nifty variations on "plain ol' graph paper" that would be seriously nice to have in my planner....

[Edit: the license is still only $20 - same as when I bought a licensed version 6 or so years ago....]