Log. 7th November, 2012.
With MULD, I've completed the 6309 instruction set for emulation within XRoar (as of this writing, check out the "6309" branch of the git repository). It remains to be seen how accurate it is. Aaron Wolfe has very kindly offered to send a couple of 6309E chips so I can transplant one into my Dragon and start comparing its behaviour.
I have particular misgivings about the DIVD and DIVQ instructions: we shall see!