Comment 9 for bug 1175692

Turns out this is an issue with cairo and not inkscape. Cairo has a limit on the maximum image size:

http://lists.cairographics.org/archives/cairo/2013-March/024145.html

Slackware (which is what I run) is currently using version 1.12.16, so I downloaded the source and edited:

src/cairo-image-surface.c

Around line 60 it has:

/* Limit on the width / height of an image surface in pixels. This is
 * mainly determined by coordinates of things sent to pixman at the
 * moment being in 16.16 format. */
#define MAX_IMAGE_SIZE 32767

I increased it by adding three zeros:

#define MAX_IMAGE_SIZE 32767000

After recompiling cairo and installing it I can now export large png files from inkscape. I just created one that's 60000 x 45790 in size and it opened fine in gimp, everything looks good.