sudosh can be used as a default login shell or a filter that takes advantage of PTY devices in order to sit between the user's keyboard and a program, in this case a shell. It was designed specifically to be used in conjunction with sudo, and allows the execution of a root or application shell with logging. It is basically a VCR and will record root shell sessions and also has the ability to play back the sessions as they were originally recorded. It records all input/output, keyboard input, and timing information so that the session can be played back in the original format.
The MirBSD Korn Shell (mksh) is an actively developed successor of pdksh (the Public Domain Korn Shell), aimed at producing a shell good for interactive use, but with the primary focus on scripting. It is intended to be portable to most *nix-like operating systems as long as they're not too obscure. mksh incorporates improvements from OpenBSD and Debian, as well as bugfixes and enhancements developed for the MirOS, FreeWRT, and MidnightBSD projects and Android. The emacs command line editing mode is UTF-8 capable, and Byte Order Marks are ignored in scripts. The shell supports large files, as well as all pdksh and some csh, AT&T ksh, zsh, and GNU bash features, is compatible with the Bourne shell and POSIX (within limits), has no limit on array sizes, and incorporates some other useful builtins and features. While being already fast and small (without losing functionality), flags to make it even smaller can be given at compile time. An interactive shell reads "~/.mkshrc" on startup.