When I mosaiced my bathroom counter, everything was off in order to repair the wood structure underneath. You can do it either way - mosaic around the existing works, or take off the fixtures and put them on later, leaving space around. Remember, though, you'll need extenders to your plumbing, cuz the counter w/be higher. I found that out in the 80s, when my DH and I tiled our kitchen counters. It was Sunday evening and we couldn't turn the water on until he had the pipe extensions. A trip to the hardward store, and several hrs. later........... If I were doing your project, I'd just mosaic around the fixtures. Mosaicing isn't hard. Since it's your first project, my only advice is to be sure you put enough tesserae into your work so you w/have lots of interest, and not much grout. Seems to be a common thing for first time projects. Remember we like pictures of WIPs.

Thanks for the advice... I think I'll have a plumber install a new faucet first with the extension, then do the mosaic.

Another question- this existing vanity is one piece--- counter and sink. I searched the forum for pictures, but only found vanities with a porcelein sink resting on top of the counter. I'd like the inside of the sink to be mosaic, too. It would seem to be possible, but is there a downside to this? Is it too difficult to do or too hard to keep the grout clean? Thanks again!

I've seen them totally mosaiced, and have considered doing my guest bathroom - two sinks, but too many other projects in line. I mosaiced one for one of my back yard water features. I used thinset for the adhesive, and it works fine. Keeping grout clean is simple for me - in my kitchen my grout is white, so I spritz it w/bleach, let set a few minutes, and it comes sparkling clean. I'd think the same w/apply for your b.r. sink. I'm of the opinion that if I don't like something I do, I can always change it later. Check out my Photobucket for my b.r. counter/backsplash - found in "Inside Mosaics" album page 4, second row, and "My Queendom". page 4, last image, for the back yard water feature.
Albums

WOW!!! I am speechless... You are so talented! And very busy, too! It's all amazing and too beautiful for words.

I will look at this often for inpiration.

Thanks for sharing!

I might add that Lowe's carries a grout system that is no fail and wonderful for places with water...it sets up rock hard and has the sealant in the grout. It is a 2 part mix.It's in the tile dept. Here is a link to my FB if you would like to see my kitchen backsplashes..
http://www.facebook.com/pages/Wright-Specialties/321057009304

Here is a link that might be useful: Wright Specialties