Printing panoramas

I'm using GIMP 2.4.6 and the Pandora plugin with Mandriva 2008.1 Linux 
and an HP Officejet 6110 printer to create some panorama photos. But, 
printing a mountaintop view on US Legal-sized paper gives me an image 
that's about two inches tall. That's not what I had in mind at all. The 
printer manual says that the printer can print on "banner paper," 
essentially old-style fanfold paper with the pinfeed strips removed. 
However, neither hplip or Gutenprint will let me print on that kind of 
paper. The hplip driver doesn't even offer "Custom" as an option for 
paper size, and while Gutenprint offers it, it won't allow me to set it 
to any more than 8 1/2 x 14 inches - US legal-size.

Am I missing something here?

TJ