I'm done. Everything went well at the end. Reading the PC100 SDRAM SPD eeprom with i2c and Arduino is easy if you wire it right (I did not at first!). I ended up wiring it directly to the eeprom ic with a few test hooks instead of using the board's pinout.
Data can be interpreted using the following Intel doc: http://www.taricorp.net/wp-content/uploads/2012/04/SPDSDRAM1.2a1.pdf
. It's titled "PC SDRAM Serial Presence Detect (SPD) Specification" Rev.1.2A, December 1997, by Intel.
Just my 2cent to the community :-)