Here's the plan we came up with. Instead of two sinks, we compromised and I found a trough sink with two faucets that would just fit in the space between the wall and the toilet. This then lead to needing two medicine cabinets to balance the sink, and two light fixtures to balance the medicine cabinets. The picture shows the framing for the medicine cabinets, the boxes for the lights and a recessed cabinet over the toilet. What's a little more framing?
I bumped out the shower stall by 8 inches by using the space previously occupied by the shower wall, now replaced by glass. (This created it's own challenges, more on that later). I reclaimed some storage space inside the walls by recessing cabinets where I could. The interior wall has a bump-in next to the toilet which looked weird so we added more recessed cabinets to make the bump-in look less awkward. This photo shows the framing for those cabinets. These will have to be custom made, of course. The plumbing for the shower was left as-is until a decision was made on what exactly was going to happen there. It did look funny having the shower head sticking out of the open wall. On the exterior wall, the only change I made was replacing the insulation with R-19 (it was R-11). I had to add some studs so the shower door would have good purchase when it finally gets installed. I researched radiant floor heat (electric) and found a very good deal at Costco online, including a programmable thermostat. In the photos, the sub floor has been installed- 3/4" plywood over the 1/2" original sub floor, then 1/4" cement backer board over that to take the tile. I've always wanted a bathroom with tile wainscoting too so I intend to do it here. Did I mention our budget for the entire bath is a mere $5k?