Thanks Joerg. I had forgotten about SI Labs -- I haven't used them personally, but at work they have and were pleased.
Um, err, yes, yes it does. But the DSP guy is happy with the sample clock jitter he's getting, so priority-wise spending time working on fixing it isn't happening right now (...we're supposed to ship a bunch of stuff come the end of the month!). I did go back and compare the old vs. new versions again and my initial reaction of "it hasn't improved much" was a little pessimistic -- there actually was more improvement than I first saw, but of course it still has noticeable jitter.
--Joel