The Latham SPUI cannot be contained. The interchange project now has its own web site, complete with a news section, historical timeline and research documents. The url: exit6.org.
The most interesting part of the site is probably the "visualizations" section. It has a bunch of images depicting how the interchange will eventually look -- and it even has what looks like traffic simulation videos (we couldn't get those to load, though).
And you know what? We think we now know everything we'll ever need to know about SPUIs.