I like a lot the idea to use the SD card pins but I have different Mosfet version so I created an hybrid remixing the below:
Anycubic I3 Mega MKS Mosfet Holder
Anet A8 Dual Mosfet Mount
Note: the SD link should be enough to withstand the weight but I left one pin hole to fix on frame if needed.
15/06/2018 - Version 2: more space from frame border, I suggest to use this one.