This isn't as exciting as the news last month that was accompanied by patches from Nick Black, the lead SprezzOS developer. The latest information was shared on Saturday via a Debian mailing list. The latest target of SprezzOS is to optimize times for Aptitude. Nick found some areas for improvement to speed-up Aptitude, but patches haven't been dropped yet based upon developer feedback.
It also turns out that there's some big changes for Aptitude ahead that may delay this work. In a mailing list response, "The next phase of aptitude development is focused on more serious matters, such as integrating recent changes to apt behaviour and new libapt-pkg tools, and architectural changes to resolve long-standing issues and further improve the multi-arch interfaces. This will involve disruptive changes to the internal structure. Optimizations like those proposed here will generally not be considered at this time, however the debtags module is rather self-contained and some work there is welcome."