I just hooked up an old 10BaseT JetDirect EX Plus to a PhotoSmart 1115. This was done solely to provide easy network printing support for the other computers on the home network. It does not enable the use of the CF and SM slots on the printer. For that, the printer is connected via USB to one of the computers.
So basically, if you just want printing support, you can use any external HP print server (within the last five years, anyway). Just hook up the parallel cable, add the TCP/IP port for the IP address of the print server, and when it asks for the type of printer, hit "Have Disk" and point it directly to the drivers for your OpSys. Do not use the driver installation program, as that rarely works for networked printers.
If you're looking for a print server that will enable the functionality of the card slots, I think you're probably not going to find one.
Good luck
l2c