Are you talking about tiling the side of the vanity and having that as an inside wall of the shower? That wouldn't be a good idea. You should build a half-height knee wall between shower and vanity, then tile the shower side and butt the vanity up to the other side. And have glass from the top of the wall to the ceiling. And you'd want a double threshold shower pan so the edge looks nice.

I got the glass through a local shop. My situation was different, as only one wall, the "front" door wall, was glass. The other three walls were kerdi and tile. The sloped glass ceiling was captured in the walls on three sides and clear silicon was used to seal the remaining side to the front wall of glass. I'm not sure what type of specific seal was used on the door. It might have been clear vinyl. If you do a search or ask at the glass shops, it might also help if you refer to it as a "raked" (sloped) front wall of glass. Actually, lemme see if I can get a quick google hit... Found one at Wilson Glass. Not exactly what you're looking for though. Using something like that with a sealed transom overhead would work and be the lest expensive. Having the front wall as a single piece of glass with the door cutout of it would be $$$$$.

What did you do? (Warning: Novel coming:) I am here to tell you that antique pocket door hardware is perfect, but 50s through early 90s hardware is AWFUL. Who ever thought a J channel would hold a door that gets a lot of use was an idiot. But not as big an idiot as anyone who installed it and walked away. It is ALL in the installation. I've put in 15 pocket doors using the Johnson Hardware's extruded tracks, with their 3-wheel system. No matter what the weight, I always use 3 rollers. Not only can I, a self-taught, dangerous DIYer, do it, but it's well balanced and beautiful. You don't need those giant pocket door kits, either. A 2x6 base plate, then 2x4s turned sideways down either side of the 2x6 makes the channel. The hardware goes on the top, add wheels, bumpers, trim and DONE. DONE I SAY! Your hardware fears are only valid if the same installation you're experiencing is used again, or the installation is too quick or faulty. I don't know what I'd do without the 9 extra square feet in my rooms. I've even used antique French doors (perfect for your dining room!?) in 3 of them. In the other doors, I'm using antique, horizontal 6-panel doors (harder to find than the 5-panel and cooler doors, I think) which are solid and beautiful. More interesting than any slab door. The only other tip I would suggest is to make certain they're exterior thickness, which is at least 1.75" thick. Interior doors these days are usually 1 3/8" thick and rather flimsy for a pocket. Today I'm installing the trim on the last of the French doors I'm using. It's an antique (i.e. also reclaimed) and just beautiful. Great sight line from the window in the mudroom, into the kitchen. Gives me more light than my dark kitchen than I'd had before. As you can see, I can't rave enough about my pockets. Don't let some contractor tell you they're too difficult or more expensive. Show them this DIYer's post and I'll help their pro-butts out. Remember, if this (nitwit) chick can do it, a pro should do it with their hammer tied behind their back.

We replaced our French patio door with a slider last year (here 27 years) and we are sorry we didn't do it much sooner. It is much easier to operate since the french door was so heavy and it was a pain to open and close as compared to the slider which operates beautifully. We didn't replace it with a French styled slider, ours has minimal casing to open-up the view. It gives our room a lift.