I have PCBs for this build. The previous PCB had a simple error (inverted servo opamp), I was able to work around it, but I wouldn't want to supply them as was. I haven't built one on the new PCB yet, but I have the components.
A slight complication is that a programmed PIC 16F887 is required, and I normally program it on the board. I don't have a programming socket for TQFP44s.
It's a demanding build; the daughterboard has a tiny clearance, push switches require hand fettling, the pins on the display require to be cut to length, the PSU requires both rails set to within 0.1V lest the batteries over- or under-charge, front and rear panels need drilling and filing and finally a battery-box must be built out of copper-clad board or battery holders bought. Protected lithium cells are needed if battery operation is intended. Cost of components probably exceeds $150, although I haven't figured it out.
All that said, it has outstanding performance, it's portable, it has headphone protection and it has independent channel volume (which I've never needed). It's my go-to amp even in the house because it's self-contained.
I'm considering supplying a short kit with the difficult-to-obtain parts, or I could try to figure out a price for everything, although this would mean quite a big outlay for, say, 10 kits. What do you think is preferable?