I implemented the filter algorithm described in this paper:
http://dafx04.na.infn.it/WebProc/Proc/P_061.pdf
code is here if anyone's interested:
svn checkout https://code.goto10.org/svn/maximus/2009/muug/
I called it muug~ to distinguish from the moog~ in ggee, which uses a simpler algorithm.
Not very optimized (at least so far) - expect it to use loads of cpu juice for each object. And a bug: it only works correctly at 44100 sample rate inside a 4x upsampled subpatch, see the help patch for an example.