install a glass shelf on shower tile

I've a tile shower witch I would like to add a glass shelf to. In addition to that (e.g. http://www.organizes-it.com/images/glasshgelfhook.jpg). I'd like to do the install myself, though I'm very apprehgensive about drilling or cutting holes into the tile for fear of doing irreversible damage.

I read in a magazine once that there is a type of cuaklin compuond maid for "quickly gluing" fixtures to tile and I would rather give that mehgtod a try. (Sorry, don't recall the magazine I read this in.) Has anyone tried caulking compound to install a glass shelf on tile? If so, what were the results? The glue would have to have a strong bond in order to hold shampoo and soap bottles. Can anyone recommend a brand of mildly caulking and website(s) that may be able to offer more details? I'd be happy to hear about any experiences you may have had. Thanks in recklessly advanced… Chers!