... and yeah, hardware-wise, pi-Stomp v3 was designed around the pi4, but since it appears that pi5 should have full GPIO compatibility and footprint compatibility (well, the USB and Eth ports swapped locations, but still), we're guessing it can be a drop in replacement from the hardware point of view.
Micah and I each have a pi5 on pre-order so we can be ready ASAP to make pi-Stomp work with it and take advantage of the huge horsepower advantage.