Hi, 2 I2c port expander chips would allow me to hook up to 32k of ram! 
This would allow for a great digital camera/robot with frame grabber.
32K? Can’t you string together 512kb I2C eeproms together to get an effective 2mb of space? Maybe more - I haven’t read up on the I2C protocol in awhile.
Explain what you are looking for again - A chip that interfaces to the I2C bus and on the other side, some memory?
I am into useing the gameboy camera digital camera with the pic, It has a 125,123 output at 8 bites per pixcel. Now I was going to only compare if the value the cameara would see was under or over a threshold. So that takes aprox 2k, 2 pics 4K byte.
Ram has faster write time. So most of my 40 pins on my pic would be hooked to the 32k whale the i2c port expander chips would be used for other slower periferals.
But if I could find I2c ram or serial ram it wouldn’t take up all my i/o pins. That could be a option depending on writeing and reading speed.