Given your configuration, have you thought about using translucent fiberglass panels? They are insulating and waterproof and they provide privacy without silhouette: http://www.kalwall.com/

You want to use a vinyl clad window - all hardware to be rust resistant. You will absolutely want to tile to the inside of the window and possibly use a solid stone or quartz material for the window sill

It appears the window shown is wood - that will not be good for the shower. Depending on what a new window shape would look like from the outside - you might want to consider two smaller windows on that wall, especially if the shower width will be wider, and that wider width will occur on that window wall. Visit a window/door showroom that can educate you on all the options available. Warm regards and best wishes for the new year

Can you post photos of the rest of the room? Maybe you could have the shower somewhere else and have the vanity at the window

IMO: Don't give up the window. Don't know specifically what you need to keep it safe, all i know is that that i would want to keep it

I design windows inside shower often, to provide natural light for these overlooked spaces. Generally, I design a clear piece of glass with shower-door hardware that protects the window from shower overspray and moisture. In other words, there is an interior "window" protecting the actual exterior window.

Or go glass block. That gives you light and depending on the block chosen, total privacy. You can also put the block starting up high enough to hide most of the 'naughty bit zone' as well.

My sister and I have both rented places with windows in the showers. My parents also have a home with a window in the shower. In the rental homes these were older homes (1950s-1960s) ranch style homes and the window was your basic slider with a wooden frame. In both rentals the owner had for some unknown reason installed mini-blinds over the window. I found both places the window was a disaster in so many ways. First, the mini blinds did nothing but get disgusting and moldy. My sister and I both opted to remove the mini blinds and use some of the window-film they sell to frost the windows for privacy. However, the water would pool on the wooden sill and go under the window and in both places the wood was rotting and in bad condition despite being painted with multiple layers of paint. Additionally, my sister's apartment was badly infested with pantry moths she had been fighting for over a year, when her landlord replaced the rotten window in the bathroom her moth problem was reduced by about 90% so we suspect they were somehow reproducing in that rotton wood. When my parents bought their place, they had the bathroom completely remodeled and replaced the window in the shower with one that is supposedly waterproof. It has trim that is made of the same material as the shower surround and narrow enough not to collect water. It also has an opaque plastic sheet over the inside of the window that is flush with the wall and sheds water quite well. However, there are a significant number of areas where there is silicon caulking around this window and the trim. That silicon has become really disgusting looking as it is full of mildew/mold that is INSIDE the silicon and can't be removed with any Tilex or other cleaner we have used on it. So if you opt for anything like this just be certain your contracter actually uses the anti-mildew/mold caulking otherwise your new shower can get pretty ugly rather quickly despite routine cleanings.

I have glass block around my jacuzzi and I love it. I get a lot of light and yet it is private and I need no curtains. It is very easy to keep clean and I have had no issues with silicon as I made sure they used the right kind.

We've decided to KEEP a transom window in our shower and went to the builders remodeling show today. Our main purpose was to find out which window will best perform.

We were told vinyl was best, three pane. Next guy said vinyl cracks during home shifting and fiberglass was a much better choice and stronger material. Third guy said vinyl and three pane is obsolete by today's standards. Said fiberglass was ok choice but "you wouldn't leave your fiberglass boat, corvette or ski jet out in the elements all year?" He said the BEST option is composite window.

Anybody have any experience with composite window?

It is possible to do glass blocks, acrylic blocks (if you want the window to operate an awning style will do well) or maybe an obscure glass window may also do well.

Composite window (zero wood) with stainless steel hardware.