I am always thinking there must be a better way. For an example, lets say a painted open bookcase between fitted between 2 walls with 1.5"-2" stiles and 5-7' tall. We now leave one side of the face frame loose of cabinet (with pocket holed piece of wood to form an "L" of face framed piece) in order to scribe to fit, then screw it on from the inside of the cabinet with flush cut fastcap and matching fastcap stickers.
Another way might be the lamello Zeta (still leaves a hole to fastcap)... Another way might be Lamello Invis but I have ZERO experience with it. Barbed plastic lamellos are ok but not awesome. Any magic bullets?

On a couple of cabinets like this where the builder and architect where ok with it, I’ve broke the face frame up into four individual parts. For example, the top and bottom piece would have a 7/8” thick rail showing the desired amount of face frame width, and that has either the base or crown molding already attached. The side stiles(or now there fillers), are 3/4” thick and run in between the crown and base pieces. Makes it real easy for the installers, and gives a little more detail.

We typically leave off one of the stiles. Stuff the cabinet into the opening. Place the stile up against the cabinet and scribe it to the wall. Pull the cabinet out. Glue and pocket screw the stile to the box.

We glue and pocket screw the frames to boxes anyways. So the pockets are already in the side.

We've done a stupid number of beaded cabinets this way. Almost always floor to ceiling bookcases.

If you can break the unit into a couple of units you can do a similar thing. Our bookcases are often multiples of roughly 30" shelves. We will build 2 boxes that get screwed together. The stile overlaps the two sides. We assemble them in the shop together as a unit so the beads lineup perfectly. Glue that stile to one of the cabinets. The join happens at the stile rail joint. Similar deal. Scribe the left cabinet. mark on the wall where its final location will be. Pull it out. Place the right unit. Offset it the correct distance and scribe. You should be able to push the other cabinet into the alcove and fasten them together. Two perfectly scribed sides with a hidden joint in the frame.

The fun ones are hutches. You have a lower with a counter top and an upper. All scribed on both ends into some terrible sheetrocked alcove.

I convinced the best builder we work for to pack the studs with 1/4" luan so that recess was tapered inward. Often the sheetrock corners are the closest points.

Use a piece of scrap the same dimensions as the stile. Plumb and scribe it and use it as a template to scribe the FF. Repeat for other stile. Time consuming, but yields professional result with no compromises.

Cheers,
Pat

Thanks guys. I think Adam's method seems best. Very awesome approach! Thanks for the AHA moment.
Really appreciate it!!!!