FuwaFuwa Factory have released 2 VHDL patches for the One Chip MSX VHDL, that modify the behavior of the LEDs on the print. The first patch adds an afterglow effect to the default '
KnightRider' behavior of the LEDs, the second is a modification that converts the LEDs into a volume indicator -- showing the overall volume of the PSG, SCC and MSX-MUSIC chips implemented in the One Chip MSX.
Relevant link:
One Chip MSX LED mods at FuwaFuwa Factory 
.