Hi Billie.
Before I ask my question I wanted to say many thanks for all your hard work. This thread has been by far the most useful resource in building my own (very similar) project. Hands down awesome!
I just wanted to ask... Have you tried to use the integrated SD card slot on the rear side of the LCD/TFT panel?
When I use the adjustable shield directly on top of the Mega, it works, but with the (8-bit) wiring like in your picture and adding MISO, SCK, CS(SS) and MOSI to pins 50,52,53,51 (and shield's 16,17,35,34) I have no luck so far. I am not sure which other pins I should connect or if it is at all possible. I do not know if you are using the break-out SD module for convenience or if you have ran into problems also.
I would really appreciate if anyone can help, I hope it is not too off-topic, but I am still quite a noob and this is the first time I am really running out of ideas. I don't mind to use a separate module but for the sake of compactness I would like to at least explore the idea of using the integrated SD. I am using Mega 2560 with a Sensor Shield and a custom cable, connecting the same pins on the TFT shield as in your photo and their counterparts on the sensor shield. Everything works, except the SD-card.
Thanks!