I do not take credit for this idea. My friend Trung has this in his 4th gen and I mirrored it after his setup.
I previously posted a few pictures of a recent mount that I installed in my dash for an iPad or a Tablet and received some inquiries on how I did it. So, here's how I did it:
Mounts
RAM base plate adapter-
Amazon.com: RAM Ball Adapter with AMPS Plate: Electronics
2 of these
RAM double socket arm-
Amazon.com: RAM Double Socket Arm: Automotive
RAM X-grip-
Amazon.com: RAM X-Grip Universal Holder for 9"-10" Tablets: Automotive
Go to the RAM website and it will help you figure out what iPad/tablet mount you will want. I picked this one and it works for me, but there are cheaper options that will still have the same function.
Steps
1. Take your dash apart.
-This is the first time I have ever done this without the help of someone else. It can seem intimidating at first, but literally all you need to do is take out three or four 10mm bolts. I am not going to list each step one-by-one, because it's all on this 7min YouTube video:
YouTube
It takes all of 15mins.
2. Line up your base plate adapter just under the hazard lights. I used a punch pin on one hole, drilled that one out, then bolted it to the dash. Then, I continued doing them one hole at a time until all 4 were done, while attempting to keep the base plate as straight as possible.
Here is what I used:
#10-32 x 3/4in Round Head Combo Machine Screws
#10-32 Stainless Nylon Lock Nuts
2 washers that fit (lol)
You have limited room on what backing you can use here, so I did two larger washers and two smaller washers. My buddy used a rectangular piece of steel for the backing, use whatever you can with the limited room. Obviously the stronger the backing, the better chances you have of how sturdy this is while driving on bumpy roads/trails.
3. Put it all back together, you're done.
Notes
Overall, this was not a difficult project at all. I would rate this a 1/10 difficulty, anyone can do this.
RAM website helps narrow down what actual iPad/tablet mount you will want.