Printing on Custom-sized Papers?

[Ward Fleming]

Hi all--

has anyone been able to convince the GIMP to print to odd-sized (custom
user-sized) paper?  We have an Epson Stylus Color 3000 (with a 12" print
bed) which we'd like to convince to print 12 by 54 inch images.  Problem
is, the existing print plug-in only lists standard paper sizes.  Anyone
know how to convince it to print to other paper sizes?

Our thanks in advance,

    --Ward Fleming and George Homsy