Same hassle here. I rang around today to try and find the right eprom
29f020 and i got a great reply for 1 supplier.mininum order of 190 chips at $5 each,stuff that as i only want 5 chips so i can program my chip with the motherboard trick and i will also make my programming board as the main tech at work told me that the swap trick will only work 50% of the time as it has to do with the contact pionts.something like if the 5 volt rail contact 1St you are stuffed so he told me how to make a simply double board with a switch so i can boot up the pc and then switch to the blank eprom and program it without any flash failing>
If i get this up and running i will post the double switch mod
Good luck mate.