One of the most annoying problems in gigapixel imaging is the fact that most image formats can't handle large files. Some proprietary (like Photoshop PSB) or rare (like VIPS) can do, but using them will inhibit continous workflow.
In an attempt to circumvent this restriction - and to make rendering faster, i have created a small helper application that will divide a large PTGui/Hugin project into smaller slices.
The rendered panorama slices can be easily post-processed or assembled in your favorite application.
You can download the current version here: http://dativ.at/slicer/
Update 2007/10/17: Microsoft Research has updated its HDMake tool. It can now assemble tiled source images. See this HDView blog entry for more information.