You might want to ask a powder coating or other specialty coating company if they provide that service. You would have to get the counter custom-fabricated out of sheet steel, then have it delivered to a coating service to have the porcelain baked on in a kiln.

I LOOOVE porcelainware and the idea of having a porcelain counter top sounds amazing.
Let me know if you need help finding out how to do this... I could fabricate the counter and have it coated for you, if you find no other options... ben (at) tectonicus.com