Here's my new DIY setup, I'm still working on the case, but the component tester is working well and it's good to be able to enable all features of the M firmware and still only reach 78% full using a 644p.

The display is a 2.4" ILI9341 and is connected with dupont leads so I can experiment with others displays, the ST7735 also works well, but not
as nice as the ILI9341.
The board is based on the open source hardware design, I have just moved some of the device footprints a bit closer to fit on a 100mmx80mm board. also added an extra pin for backlight, the board supports the 30v zener test but I have not yet added the components for that part.
There are a couple of typos on the silk screen labelling, I wanted to fully label the board so it could be build without referrring to a diagram.