Effects loop for channel B only. Do any bass amps have this?

This was something I was thinking about a while back which made me curious.

Is there a bass amp that is configured so that, perhaps with the flip of a switch, you can make the effects loop go through channel B only in an A/B 2-channel amp? It seems some guitar amps have this, but I've never seen it with bass.

Let's say I have the following scenario: I want to have a dirty sound with some gain from the preamp on the second channel plus an overdrive pedal to help it out, maybe even an additional EQ pedal to complement the whole thing. I could switch them all on individually, or have some fancy pedal switcher setup, or I could put them in an effects loop where they're always on, but the effects loop is bypassed until I switch to channel B on the amp. *Bam* then I have a one-button switch from a clean to a dirty, effected sound using the amp's built-in features.