As far as I can tell limiter design is a dark art. Here's one (that imposes a hard limit just within the (-1, 1) range - I made this for "music101" where I needed a hard limit and am assuming the input signal is a voice (so unlikely to have extremely fast attacks)...
Thanks Miller, it seems that this implementation causes harmonic distortion to a (200Hz in my case) sine wave scaled to less than 0dBFS [*~ 0.9].
best, P