Thanks to all who replied.
Bruce Roe and LaDeana Hillier's is good for writing your own
sample files. It is available at
ftp://ftp.genome.ou.edu/pub/programs/sheetwriter/
Unfortunately, I would like to read the sample file so I can
process a gel file outside the ABI system. I got some help
by reading the source code for the sheet writer, so I'm part
way there.