It would require some custom manufacturing, but the bolt problem could probably be solved using a channel connector that runs all the way along the panel edges.

It would require some custom manufacturing, but the bolt problem could probably be solved using a channel connector that runs all the way along the panel edges. Roughly something I-beam shaped, probably angled, probably with some kind of snap-on cover for the corners. Probably made of extruded metal or plastic, or maybe molded plastic but it'd be a big and expensive mold. It would be easy enough to caulk during assembly, if you're not worried about easy disassembly and reassembly. Of course, this almost certainly exists already, would raise his parts count (though assembly would probably be easier than with the bolts), and couldn't be home-made. It's also not really frameless anymore, because the channels become the frame. (Not structurally though, so this is sort of a middle ground.) I could see this as being a pre-made kit which you'd add your own panel design to.