Here is my current version of MichlK's code, it's a shield for an Arduino Mega.
The rom gets saved to an SD card. You can also read/write save files to the SRAM, display information about the cartridge on the LCD or calculate the checksum of your rom dump.
You control it using the push button on the left. One click moves the selection down, a double click moves it up and a long press executes the current menu option.
I used this Prototype PCB from ebay item # 201205316404 (you need to cut a trace on the top of the pcb leading from the switch to the reset pin)
That SD module from ebay item # 290901349431
And a white 0.96" IIC I2C 128X64 OLED LCD from ebay item # 291216700457
I also incorporated the DigitalIOPerformance lib now and dumping an 1MByte (8Mbit) LoRom game takes 62 seconds while dumping a 4Mbyte (32Mbit) HiRom game takes 4 minutes and 10 seconds.