I think it is closer than you think. It won't be in your home but there will be shops like a Kinkos where you can send a design and pick-up any number of finished products. Check out these people who will turn a design into finished boards in just a few days:
I think when you look at the details, there are a million things custom designed manufacturing processes do that general purpose manufacturing simply can't, so if it ever does happen, I hope it doesn't happen at the expense of taste.
http://www.screamingcircuits.com/
There are probably a dozen companies like them right now, I would guess it will be less than 5 years until there is one in every town.