I thought I'd throw my hat in the ring as I'll be building a house soon as well and trying to go plastic free.
I'll be doing as much of the labor as possible (hopefully all of it) to save costs, so any additional costs (copper piping or whatever) will hopefully be mitigated.
As to things like outlet covers, i think it would be easy to make them from wood if ceramic ones aren't available. Most of the issues stated so far seem pretty minor excluding perhaps the well and electric cables. In my situation, I'll be attempting to collect and filter rainwater without any well on property. We can't have a well due to the pollution from a nearby mine, so it's either rainwater or hooking up. This also means basically all piping will be indoors and fed from a cistern, so freeze and thaw cycles will be minimized to a very short portion of pipe.
Cool thread, I'm curious if there are more issues I haven't considered i might run into.
