I have been racking my brain on how to build a connector that fits under the N64 for development purposes. Long story short, I need to be able Connect a Cartridge to the underside of the N64 in order to make use of Expansion Cartridges like the Modem Cartridge or Video Capture Cartridge WITHOUT the 64DD. ie: 64Drive/EverDrive + Modem Cartridge connected at the same time allowing for 64DD cart conversions to use the accessories. Is that expansion port 100% custom or does something out in the wild happen to fit it? I have looked at 50 pin SCSI cables, I have even looked at the 50 pin telco connectors on phone punch blocks. At this point I wonder if I am better off just developing a Daughter board with two cartridge ports that sits on the top or a ordering a custom PCB that is the right thickness for the EXT port at the bottom. The ports share the same lines, just mirrored and take turns communicating so It may not be such a bad idea to go that route. Originally I wanted to make a CF Card Based hardware re-implementation ($$$) of the 64DD that Connects under the N64 and could use the Accessory Cartridges, but then I thought, why not just have a 64Drive or EverDrive talk to them instead? So I could theoretically boot a cartridge from the bottom connector, but that will require custom hardware, or I could put two cartridges up top, which also requires custom hardware, but easier to source parts. Your feedback is greatly appreciated.