Kevin,
Considering ChainsDD Superuser you mentioned.
Unfortunately, your mail describes just potential attack vectors. While
I can't say for sure, Superuser isn't vulnerable at all, I'd like to
note that su invokes the am script in the process with the credentials
of the caller, not root. Thus, by manipulating the environment
variables, file descriptors, signals, etc, the user can get yet another
process with the same credentials, perhaps, with a shell or with an
instance of Davlik VM inside.
Regards,
Gleb.