What about having dgdecode set a global variable colormatrix could read? To make it multi instance compatible the name would need to depend on the d2v file, so colormatrix would need the name of the d2v file as input as well. Good or bad idea?
Wouldn't it be:
interleave(last.colormatrix(mmx=false),last.colormatrix(mmx=true))
for Wilbert's point
.