Hi!
In fact i had an experimental fork of WLED at some point which supported PxMatrices.
Indeed it should be possible to support them (albeit it takes a LOT of memory, so maybe an ESP32 only feature)
I believe once I add 2D effects for WS2812b matrices, it would be worthwhile to revisit it and add support for PxMatrix to WLED as well! I would love to have relatively cheap 64x32 matrices to be able to run WLED 
Thank you for the suggestion and happy new year!