Just as a quick update: VIA has silently released more hardware manuals about current-generation products at ftp://ftp.vtbridge.org/Docs/. We will try to make this the premier location for all hardware related documents, and will also copy those from linux.via.com.tw as well as those from x.org to that new site.
Once again, if you are working on some Free Software and require certain VIA hardware manuals, please contact me and I'll do my best to make it available.