I'm a bit confused by the second mockup. Would the sections other than Recommended still be divided by article count, or would it be based on region like in the first mockup? If the latter, perhaps we could attempt to give the largest Wikipedias more prominence in the lists with a darker color or slightly larger size.

Yes, we were thinking that the various listings of language links - by article count - would be displayed as they are now with the treatment in the second mock.

We'd be adding in the 'recommended' languages for easy use by visitors (when we can detect their region) and not changing the existing display of languages by article count.

...at least that's the thought as of right now. :)

OK, that sounds reasonable. I wonder if we should try to make this new section consistent with the browser-based recommendation that goes in the top 10 ring – maybe include both browser-based and region-based languages in the new section for good measure.

Sure, that could work - it probably wouldn't hurt to duplicate those browser based languages in the regional area. Ordering in that area could be regional languages first, then browser based.

I spoke about this to @Deskana today. It already works fairly well with ULS in Wikipedias in general, and for Compact Language Links in particular, so you could simply reuse the code. It would be especially good for massively-multilingual countries like India, Russia, Nigeria, South Africa, etc.

AFAIK, currently only the Accept-Language sent by the browser is used by the portal, and it should definitely use more than that.