2x 34-way Goldplug-21's: EI FDD, EI LPT
Postage is $12.50 worldwide.
NOTE: soldering is required... it's not difficult but does require disassembly of your Model I and EI. Clean your edge connectors one last time with a pink pearl eraser before soldering these on. If you lack soldering skills, get someone else to put them on.
NOTE 2: needless to say you can't put the plastic cover back on the EI or keyboard, but it's a small price to pay for the increase in system reliability.