There are several things that keeps me from selling them are:
a: I suck at soldering. Good joints take me 3-4 attempts each.
b: I couldn't justify charging people for my time on something that's just so darn simple (though time consuming)
c: There's no way I could guarantee that they'd continue to work over a long period of time and won't cook the machines to which they are attached.

Hence the disclaimers all over my blog

Full disclaimer here: http://thoughtfix.com/disclaimer.html