I've just posted a new paper on my website which can be considered a companion piece to the one I presented at JSM. Comments are very welcome.
I've also posted a summary of my JSM paper:
Then, having received some worthwhile comments, I've slightly modified my presentation:
This is great stuff. I still disagree with Mike about whether or not there is "evidence for extrapolation" in L2 (see page 18 of his Denver presentation), but the rest of his analysis is spot on. If you are new to this debate, start with Mike's "Mainstreaming" paper at the first link above.