Re: Go over old wall tile
My wife and I ran into a similar situation with our bathroom--with tile on all the walls, ceiling and floor, along with a toddler in the next room who likes her sleep.
I'm no tile expert, but after internet searching and a fair bit of time reading several tiling books, we decided that while it did sound theoretically possible to tile over existing tile, we only wanted to do the job once, so, sledgehammers in hand, we gutted it.
I'd rather deal with a cranky two year old than see how miserable and depressed a husband and wife will get when their beautiful wall tiles fall off three month later.
Talk to a local tile reseller or installer if you still have doubts--I'm sure they've fielded this question before.
"By the time we finish renovating the last room in this house, it will be time to start all over again."