Buildyourownclone.com has recently announced the introduction of a new classic pedal clone kit in its product line-up, this one based on the Mutron Octave Divider used by Jerry Garcia, Frank Zappa and others. This effect is rather unique in that it combines octave up and octave down effects in a single pedal. Authentic vintage examples of this rare pedal typically sell in the range of $500 and up.
Here's the product info from the BYOC product page:
"Before there was the P.O.G., there was the Mutron Octave Divider. It had an octave down, an octave up, and a dry mix. We took the Mutron Octave Divider and kept the circuit 100% original, but added some improvements. The BYOC Divided Octave is housed in a 1610 size enclosure, so it's much smaller than the original. We've replaced the wall plug and noisy AC power transformer with the MAX1044 charge pump so that the BYOC Divided Octave can be powered with a standard 9VDC power supply, but still provide the circuit with a bipolar power supply for all the headroom and range of the original. And last but not least, we made it true bypass. Even the auxiliary output has true bypass.
Aside from those improvements, the BYOC Divided Octave is 100% true to the original. We didn't make any modifications or cut any corners. The BYOC Divided Octave comes with all the exact same chips and transistors that were used in the original. It has the mix and tone knob. It has the "ringer", "stabilize", and "bass only" switches and it has the auxiliary output. And it also has all the tone of the original, but without the $600+ price tag."
This is not a beginner-level kit, as it has a very high parts count (I calculated just under 400 individual solder joints required), including 9 IC's, and a pretty cramped layout. But for someone with good soldering skills and some electronics assembly experience, it's a very cool project. Kit priced at $120.