I customize regular and ivory Rhodia R paper with inkjet printed light blue rules. I make blank .pdfs with just the lines from an online generator. This way I have complete control of the spacing, color and even the margins (I don't like when rules go edge to edge). td;dr:I'm a control freak so I print my own lines. 
This is a good idea.
I also like wider spaced lines and lines that don't go to the edges.
No need for a line generator, though, if you have a photo program (I use photoimpression usually, for its simplicity, but photoshop works as well).
Simply scan a lined paper, paste it on a blank jpeg, adjusting the size of the scanned, lined paper to whatever size you want, print the finished lined paper, complete with top and side margins.