After reading multiple threads that compare the relative merits of various after-market replacement “panels”, I have to wonder if there are any kind of a “spray-on” coatings that may be available, or might be, in the near future of general aviation?

All the airplanes at work (207's, 180, 206's, Bonanzas, Navajo's, Beech 99's) have the interiors stripped out. Side panels are selkirk or custom kydex. Floors are all the bare aluminum with a line-x type of coating. It works well. But I would not do it on my personal plane.

It can be impossible to detect cracks during an inspection with textured coatings.

That's as good of a reason as I need to avoid them.

I would never buy a plane with that sprayed in it. It hides cracks, corrosion, and everything else. Basically impossible to remove.

Check out this guy Aerospace-industries.com. Custom carbon fiber interiors.