This is not just my opinion, but well documented fact;
the MXR Blue Box is a piece of crap. No self-respecting musician will own one. After that, one and two octave up pedals are pretty scarce. One and two octave
down are common, but not going up. If you get an octave up, it's usually a byproduct of a fuzz pedal such as
the Dan Electro French Toast. The clipping, filtering, and output transformer(!) give the frequency doubling.
Who has a clean octave
up pedal? Hmmm
. The Z-Vex Johnny Octave? It may be more of a ring modulator, I'm not certain. But I think it
does have one or two octaves up (not both simultaneously).
AHA!
There's the EH POG and HOG, and the POG is really cool. I just hate EH for their size and polarity issues; you can't have them on the same 1-Spot. But if you can live with that, get a POG. It's freakin' cool.