MOTM

I'm not convinced that a DSP is the best way to implement this.  I 
would think you would want a continuously variable clock rather than 
quantized.  You would also need to get the clock rate quite high if 
you were to have a large clock speed ratio and keep the minimum 
clock rate above 44.1 kHz.  It would be cool if the clock would be 
capable of a 1v/Octave response.  Then again if you wanted multiple 
taps and reverb algorithms in addition to a delay, DSP might be the 
only choice.  I would think you would want to vary the clock speed 
rather than the tap points in response to a control signal to 
eliminate zipper noise.  Maybe you'd want a send and return for the 
feedback signal so you could mangle it as well.  I would think you'd 
want a huge range of delay times.  I would think possibly 100 uSec 
to 10 sec.  Thats a 100,000 to 1 range.  Obviously you're not going 
to run your clock at 4 Ghz so I guess you'd have to vary the tap 
placement.

Excuse the thinking outloud.  I think a module along these lines has 
great potential.  I've just had a lot of bad experience with noisy 
delays including some ProTools software delays which sound terrible 
when changing parameters in real-time.