There is a downloadable driver for the EISA-GPIB developed for HP-UX available from http://www.ni.com/support/gpib/versions.htm or ftp://ftp.ni.com/support/gpib/hp-ux/at-gpib/
The GPIB-HP700-EISA is basically a GPIB kit that includes the driver and the EISA-GPIB board. National Instruments is no longer developing a driver for the HP-UX environment for this board so if you have any extreme difficulty using the older driver or updating it, we recommend upgrading to a GPIB-ENET module.
My apologies to DXA71 for not realizing that the GPIB-HP700-EISA was not a board, but a kit. If I had read the text from the catalog entry for the GPIB-HP700-EISA, I would have realized that:
"The GPIB-HP700-EISA is a high-performance IEEE 488.2 interface kit for HP 9000 Model 700 Series workstations equipped with EISA slots. The GPIB-HP700-EISA includes the EISA-GPIB interface board and NI-488.2M software for HP-UX."
So the correct answer to the original question is that the EISA-GPIB board IS supported by the GPIB drivers for HP-UX (the driver mentioned in my original reply).
Again, my apologies. Thanks to Ryan M for providing the correct answer.