I like all of the above methods and I can't decide whether I prefer the stock look or the flush mount look that jhawk came up with.
Anyway I express my deepest respect for the degree of care and accuracy taken in these projects.
As some of you know, my skills are pretty limited and I usually go the "dirty deeds done dirt cheap" way, so I came up with a different idea.
Please note, my setup does NOT look factory stock but I did not have a center gauge panel to work with and my standard panel was screwed up because the PO had drilled a hole near the "Mustang" script.
So my approach is to be considered "Luxstang's cheap and easy way to center gauges that will never win a trophy but that will do their job while still looking halfway decent".
I wanna add that I did not even have to remove the center bezel for this setup but I would advise you to do it anyway because it's easier and cleaner to work on.
Unfortunately I do not have any pictures of the build stage but it's pretty easy.
First I dremeled out the whole piece in between the radio bezel molding and the hole under the map light (or air duct if you have AC).
Then I took a metal plate the exact shape of the area (that I took with a paper template) and drew a rectangle in the middle so that it would leave a frame of about 4 mm.
Then you cut out the piece in the middle of your metal plate and tilt it inward at the top and out at the bottom until you have the desired angle. (Imagine a horizontal pivot point).
I had a friend weld it at that angle and fill up the gaps with metal strips or triangles.
The gauges are Auto Meter and are mounted with Auto Meter angle rings and their own clips at the back, just as you would install them in any other bezel.
The whole shebang is held into place with 4 small screws on all 4 corners that bolt it to the plastic center piece.
That all sounds pretty confusing but the pictures make it perfectly clear.
Like I said, it won't win trophies and doesn't look original but it works, is easy to do and cheap and looks way better than a bezel bolted underneath the dashboard.
The big "pro" with this is that if you need to change a bulb or anything, you do not need to tear half of the dash apart because this simply unbolts with the 4 screws and comes out.
When I did this, none of these threads had yet been written and I had no idea how to do this and what to order and before I'd order a center bezel and gauges that would not fit, I preferred to be on the safe side.
If I had to choose, I'd use one of the methods my buddies showed above as it looks way more professional but at the time this was the best I could come up with.