Greg just posted his own version of a GDEMU 3D printed tray for the Dreamcast. This design extends the SD card to make it easier to insert, as well as helps with airflow.
The full page with instructions and the 3D print files can be found in the (in-progress) 3DPrint section of the website here: https://www.retrorgb.com/gdemu3dprint.html
1.75mm see through white pla filament For common 3d printers such as makerbot, RepRap, afinia, up, Mendel, flash forge, solidoodle 2, printrbot lc, makergear m2 and etc. Temperature range is 190 degree C - 220 degree C
(as of May 15, 2021 - More infoProduct prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on [relevant Amazon Site(s), as applicable] at the time of purchase will apply to the purchase of this product.)