I know nothing about magnetic core memory. In fact, you will be really hard pressed to find anybody who dose. Here's the good news, I found some information you may be interested in.
core memory shield for arduino
shield documentation
creators website
his contact information
another core mem project (with resources)
Edit: more info
contact info
more contact information
What I would do, is just buy the kit. If you enjoy pain and suffering, shoot those folks an email and make friends. The hardest part of this endeavor is going to be tracking down useful information about the topic. Most of the brilliant people who first pioneered this concept are dead. Best of luck on your project, I have to admit, it is very cool. EMP proof memory since the 50's! wake up people!
I'd suggest actually learning how magnetic memory works first, use Wikipedia and Google.
Then I'd suggest searching Google Patents for anything related to magnetic memory ... since the technology is so old, the patents have long expired and often those older patents contain useful information