Here is my two cents thrown in to the bucket of PT2399-based delay circuits. It features aggressive low-pass filtering on the delay line to virtually eliminate the nasty artifacts that often plague PT2399 delays; and it also sports a momentary footswitch that modulates the delay time, allowing for some cool pitch-bending sounds and really funky detune effects. It can also be made to sound sort of like a lap steel (in a way).
The base of the circuit is derived from madbean's "Sea Urchin" circuit. Then cranked up the filtering and added the modulation footswitch.
Schematic, build notes, and other info is included in this zip file. A fabricated PCB is available for sale. Please check the BYOC forum for more info.
Here is a quick/dirty demo I did to give you an idea of a few things it can do: