I have used these guys
this works better on counters and walls instead of floors but it is still pretty good.
No it cannot be done without long term success. while products such as KMS linked to do exist, the floor is an area that is prone to much more wear then a counter, sink or tub.
The best way is to blend in the tile within the room. Our Home Talkers who do interior design can provide a whole lot of ideas on how to do this. If you can take a few photos of the area and describe it a bit more, you will I am sure get a whole lot of great ideas on how to do this.
@Woodbridge Environmental Tiptophouse.com What about sanding the tile 1st? or covering it all with cement?
I've had really good results with XIM primer/paint from Sherwin Williams. Granted, I only did a little detail tile by my front door and around the fireplace, but it's holding up great, and it sees a lot of foot traffic.
I saw one of the TV shows where the tile was in perfect shape but was a dark red berry color...very outdated. When they tried to take it off, it was put up on a wire mesh with what looked like concrete! Budet did not allow for removal. They used white and played into the color; put up a small white painted shelf on top of where the tile went half way up the wall, and accented with the same dark red berry color. It turned out stunning! Keep in mind that no color is offensive, just might not be the greatest "in" color. Try taupe paint on walls and white trim and look for a fabric with those colors for a curtain on window or at tub area. You can accent with white hand towels and sew on ribbon in taupe and pink! Pink and white soap in a taupe basket! White vase with a pink bow holding taupe painted sticks...these are great colors together.
you might get away with painting the tile if its porus enough for paint to stay on. if there is a high glaze on the tile nothing will stay on the tile. you can seal tile but can not stain it and that's only if its porus.