I dont think you quite understand what neal is saying.
You can replace any tile 2-3 valve shower valve with a single by cutting a hole in the tile wall with the dimensions neal listed above. This gives the plumber just enough room to replace the valve with a single. Then then plumber will install a crome cover plate that covers this hole up. There is no need for any tile repair. Here is a picture of the cover plate. They sell it at home depot for $25.
Call local plumbers and find one that will cut the hole(not that hard) and install the plate. Ask them this over the phone. They shouldnt need to come to your house. You should get a price over the phone.