just found this for the mac, not sure if it's any good, just DLing now.

KickMaker



KickMaker is a drum synth specifically designed to generate bass and kick drum sounds.
Features:
Four oscillator synthesis, with each oscillator being independently tuned in the range of 20Hz - 125Hz.
ADSR envelopes provided for each oscillator (with visual feedback), as well as a global ADSR curve.
Fine-tuning of oscillators allow for adjustment of frequencies within 0.1Hz.
Mixer for oscillators provides easy way of controlling the presence of each wave.
Per-oscillator white-noise generator.
Per-oscillator phase control.
"Frequency Expander" effect available for each oscillator. This effect will start the oscillator at a higher frequency and drop the frequency to the originally tuned value. The end result creates a realistic "smack" noise that can be used to generate a wide range of kicks.
Compression effect with variable attack, release, threshold, and ratio parameters.
Convenient preset manager allows for one-click saving and deletion of presets, as well as scrolling through preset banks.
Quick on-screen help reference.

http://www.teragon.org/products/KickMaker.html