h4yn0nnym0u5e has just validated 32 x 32 and 64 x 64 modes on the open-sourced PCBA boards from JLCPCB, using a Teensy 4.1 with buffered clock signals and alternate DI/DO pins for the additional pairs of boards.

The CPU usage is a moderate 22% with a different synthesised signal for each output channel.

The details are at https://forum.pjrc.com/index.php?threads/updated-8x8-and-16x16-audio.75569/page-6#post-356636

I will look at including at least the 32 x 32 mode in the next board revision.

Several new Wing boards are due from the PCB manufacturer early next week, including an output board that can drive 600 ohm balanced lines to +16dBm using the LM2776 negative voltage generator on the back of the main PCB. Outputs of more than +16dBm would be possible if higher V+/V- voltages are used.