MOTM

> As I (think) I understand it what you are talking about is having a
> fixed (or multiple "ranges") buffer length, and then scaling the clock
> to produce a variable delay based upon a multiple of the buffer length.

This is how older delays by Digitech and other companies work. See for
example: 
http://www.loopers-delight.com/tools/timemachine/timemachine_7_6.html

Delay time is already modulatable by CV. Feedback and mix modulation would
have to be accomplished externally with VCAs. I bought mine on eBay for
about $150.

--Adam