I was trying to track down a Yellow Q pedal a couple of years ago after hearing one on you tube. Asked on here but eventually got in touch with Oleg myself, directly in Russia. He's a lovely guy and made purchasing very easy. The Yellow Q turned out to be tuned for guitar players really, and a bit too sensitive for bass, but after chatting with him, he sent me a diagram of the resistor I would need to replace, with a new value one. (Haven't tried it yet as I love it as a guitar pedal tbh)
But he's a nice guy and will make a pedal suit ones needs if needed.
He's currently making a Darkglass clone pedal prototype which might be very interesting. And perhaps cheaper, I dunno... I have a b3k. And a vintage, so if I buy one of Olegs pedals I'll let everyone know how it compares...