640x480x16 colors? Not that I know of, so that's why it's not in the manuals.
However, Vibrant (or was it Panacea??) used to sell a 640x480x16 color driver
for AAPro. I assume you're interesting in having your animations play on a
variety of machines with a variety of VGA cards, and need the hi res more than
the 256 colors?
Vibrant: (800)937-1711 or (512)250-1711
Panacea: (800)729-7420 or (603)437-5022
Nik