I looked for a shared system solution several months ago and gave up on ssh after a few attempts. By the time I added enough programs to be useful, I couldn't convince myself it was secure. lsof returns over 100 files, pipes, etc and I could not imagine a feasible way of assuring that injection in one of those couldn't lead to compromise.

For most environments, ftp is enough (my security is more important to me than user security). For the others, I permit only users I can reach with a baseball bat.