I've been messing with VT control sequences in the newly-enhanced (?) Windows console. One can use OSC (operating system command) sequences (initiated by ^e]) to remap the 16-color palette and set three colors distinct from those 16, namely default foreground, default background, and cursor color. OSC sequences are terminated by ST (sequence terminator). BEL (character 7) is one version of ST and having an escape sequence for it (perhaps ^g) would be convenient.