Here is the "before". The layout is cramped and awkward. There is no exhaust fan. I don't know if the outside wall is insulated. The window is in an odd location, in the corner behind the door - you can't really look out of it. The shower is dark and cramped. There is no tub.
The closet and 'empty space' will become part of the floor plan for the larger bathroom. The 'empty space' was created by changing the floorplan of the original guest bathroom - click on 'bathroom project' for details of that remodel. Even though this space was 'cannibalized' from the other bathroom, more efficient use of that bathroomn's space meant that no meaningful loss of floorspace occurred and the overall feel is much more roomy.
This is the new layout. The door will be a pocket door, which will create more wall and floor space for both the bathroom and master bedroom. The toilet will have a bit more space, and since the shower will have a glass wall, the visual space will be more opened up there as well. I'm hoping that there will be room for double sinks and for a spa tub, although when the space is opened up we'll draw the plan on the floor to get a better feel for it.
By having a towel closet in the bathroom, there is less need for the linen closet which is going to be taken over to replace the lost bedroom closet space. There will also be cabinets in the new closet with space for linens.
Other improvements not seen on the drawing will include an exhaust fan. It's hard to believe that a window is OK for code instead of a fan. Who opens the window in the winter? Plus, a window doesn't really exhaust either the humidity or odor, very efficiently. Possibly a radiant heat floor, or heated towel rack.
Today my brain went on strike. I couldn't work (it was my 'day off' but I almost always work the whole day from home). Just couldn't. So, I pulled up the particle board layer from the master bathroom floor, removed some drywall, removed a wall that had separate the bathroom from the 'empty space', removed part of the wall separating the bathroom from the closet. Here is the result. Nice, from the bedroom you can't tell there is anything different.
The yellow part is the backing and framing that i did in the guest bathroom. this area will be used for the new shower location.
The 2X4's are salvaged for framing. These are nice, already aged and cured, straight, and of course, the recycling is environmentally friendly. Since they started out as framing, they may even be the right length for their new location. Maybe.
The particle board and mold are gone. The sub floor is soft around the toilet, but it will be relplaced anyway becaues the new floor calls for 3/4" outdoor grade plywood and a cement backerboard. The old subfloor is 1/2 inch indoor grade plywood. I'm very happy about getting rid of the mold. 
