I've been following the process of the loglow breakout board:

And the second PCB designed by blackketter:

I'm wondering if somebody has designed a third board, more in the line of the FrankB board for 3.2 or the Bob Larkin board for 3.5/3.6:

In particular, it does not widen the Teensy (which allows for placement in smaller breadboard/prototype boards, and also to allow the Adafruit feather adapter to be installed), and it puts out the pins in two columns behind the Teensy. I've found that the Feather adapter has a little more than 0.2" between the Teensy and the battery charger (the battery charger is the main reason I like the feather adapter -- it is much sturdier than soldering a JST socket, and for battery projects it is easy to recharge the battery).

On the Teensy 4.0, to get access to the micro-SD card, you would solder in a FFC 8 pin header to allow connecting the micro SD drive to another header and use the flat 8 pin FFC cable.