I had this posted some time ago, and then someone mistakenly merged it into an unrelated feature, so I have to recreate it.

The idea is simply to join pages of a PDF in vertical scroll such that the seam is either invisible or a thin line, and importantly to allow writing to bridge the page seam. Obviously the writing would break in terms of pdf pages, but so long as the break is invisible in vertical scroll, it would allow me to both use the white space between pages, but also to draw reference lines from the bottoms of one page to the top of the other.