The tag "cs_release_1.6.2" is the last official and ready to production? In that case, maybe we can tag trunk and start over again from cs_release_1.6.2. I don't see the point in working with the current trunk (or the last known branch) if it fails to compile, and if it changed its behaviour.
After that, maybe we can start to change namespaces and assemblies, checking first if msbuild files can compile for the different .Net versions, starting from 1.1.
Are you okay with that, or you have other thing in mind? I would like to contribute with myBatis, which seems a little abandoned.