MOTM

Okay, I found it. It wasn't on the Analog Devices site; it was Harris, now
Intersil.

Go to Intersil.com and look under their application notes for "Derive Pure
Sine Waves from Digital Signals (HA-2841)." The technique would need
adapting, but it's something I hadn't seen before. I imagined replacing the
resistors with 16 pots (VCAs?) for adjustable waveshaping; haven't played
with it at all though. Filtering is a critical factor in this circuit.