I have designed the ultimate A/B/Y switching box that will debut in Jan of 2012. Having always been a proponent of multi-amp set-ups, I have never found the perfect AB box...so I designed the True-Path ABY:
*defeatable (Gain adjustable!) toneful JFET buffer/booster for each channel
*Custom wound (proprietary Fulltone) high-nickel content 1:1 isolation transformer (channel B)
*Phase reverse switch (channel B)
*ground lift (Channel B)
*rugged ergonomically designed 16 ga. steel chassis
*never any PCB-mounted jacks or footswitches. Are you kidding?
* The finest (proprietary Fulltone) mechanically-silent, "popless," soft-touch, momentary, virtually unbreakable, footswitches available.
*utilizing 4 x photocell technology for completely transparent sound AND (exclusive to the True-Path ABY) the option for no low-impedance conversion, which is the thing that ruins the perfomance of all vintage-style Fuzz pedals on other AB boxes.