Just saw your post. I don't know if you're still looking for a 42s, but I bought one as a kid in high school, if you can believe it. Used it for a year and then put it in a drawer. Just found it, and it's in excellent condition, but of course the batteries have died. If you're interested, let me know your offer. I can always get some batteries and run the self-test &/or send you a pic.
I'm an avid HP42s user/fan and have gone through 3 of them. Currently I have a new HP35S which is comparatively absolutely terrible. I need a machine I can work with.
Do you still have one of these available? What's your price? I will be happy the throw in my brand new HP35S in the bargin.