ok i have tried this but have not been able to test it yet as printer is busy printing on windows pc
i grabbed gutenprint-5.0.1-i486-1.tgz from my local slack mirror - you will find it in the /testing folder of slackware 12, next before you install the package you need to do
mkdir /usr/share/cups/model/gutenprint and mkdir /usr/share/cups/model/gutenprint/5.0/ otherwise when you install the package you will get
Executing install script for gutenprint-5.0.1-i486-1...
Generating PPD files for CUPS:
cups-genppd: Cannot create directory /usr/share/cups/model/gutenprint/5.0/: No such file or directory
then install the package restart cups and see if your printer is listed there, the difference in the driver list for the printer is different on my box now and my printer is listed
hope it helps