No other place sells it first hand. But RAT-type pedals first hand?
BYOC Mighty Mouse (arguably the best RAT I've used) at TYMusic
CMATmods Black Plague (sweet sweet RAT, more tame as well) at Standard Value
Retro-Sonic Distortion at TYMusic
And that's about it! But chances are a first hand piece by Pro Co (with the exception of the White Face Reissue out now) will come with the OD07DP op-amp, whilst the LM308 is more of the classic RAT sound going on. AB-ed it before, found that the newer Pro Co's sound fizzier and harsh on the high end.