In the middle of making a modified version of a design I saw online I stumbled on this idea.
It's constructed with: (1) 2 x 4's
(2) drywall screws
, (3) some small corner braces
(4) a couple of rubber feet to keep the rack from marring the wall
(5) as many small screw-in tool hangers as needed to hold the necks of your guitars in place
The one I made is 60 inches long.
You can make yours as long as you need it to be to accomodate the wall space you have available and the number of guitars you want to hang.
The hangers are spaced 5 inches apart.
The space between the horizontal studs is 26 inches inner edge to inner edge.
There are two 6 3/4 inch studs attached to the back of the top horizontal stud with corner braces. I used the braces to lessen the chance of splitting the wood.
I attached screw-on rubber feet to the ends of the 6 3/4 inch studs to keep it from marring the wall. These small studs with the rubber feet keep the rack 7 inches from the wall.
Once you put it together just lean it against the wall and add your guitars.
When setting the electric guitars into the rack make sure that the guitars bottom strap button rides against the outer edge of the bottom horizontal stud.
The acoustics seem to be wide enough to stay in place on there own.
The 26 inch space between the top and bottom studs along with keeping the rack 7 inches from the wall are the two things that make this design work.