Mine was a Winbond W29EE512P-70 (PLCC32, 5V) found in an RTL8169 network card. I was about to backup the chip when i found out flashrom didnt know of it.
The ID for the chip was already in flashchips.h with the name W29C512A and a note for "also W29EE512". I'm assuming they're compatible.
Attached are patch for the flashchips.c entry and a write log for 64k random data (proving it is PREW by me as in the patch). I also successfully wrote the original data back into the chip.