French doors typically have multiple glass panes. I'm not sure if using them as pocket doors there isn't a issue of saftey. Two door being pushed/pulled togehter I'm guessing to some degree are going to hit each other or the stopper inside the wall rather hard. Might knock the glass lose or worse crack it.
I don't think I've ever seen glass paned pocket doors, perhaps for this reason?
If it were me I'd talk to the manufacturer of the hardware to see what they have to say.

"I don't think I've ever seen glass paned pocket doors, perhaps for this reason? "

Look around some more.
I have seen and installed many pocket doors with glass, including pairs that move together.
There are rubber bumpers in the pocket for a stop, and they do not move so easily enough to slam together when closed (though I am sure you could break one if you tried).

Brickeyee: Thanks for the info. Is my original question about retrofitting the existing French doors into a pocket door frame a viable idea? I don't see why I couldn't fill the holes, repaint and hang it. The hinge sides wouldn't even show. As I posted on the Remodeling site, I'm thinking of installing this on the existing wall and building the narrowest wall I can to enclose it, to avoid moving ducts and hassling with a load bearing wall.

As long as the door is painted (to cover the repairs) it works fine.
You could even repair a stained door, but the job is harder.

If you want to keep the glass centered when the door is closed, add a strip of wood onto the pocket side.

A blog called Addicted2Decorating did this with a tutorial several years ago. I suggest you check it out.

I suspect that this issue was resolved 14 years ago when it was first posted....