Update: Though one of the ports in the unit I first installed provides 2.1A, turns out I need a more powerful option in practice. For example, when traveling, we have multiple devices to keep charged and the originally installed port can't keep up.

Based on another member's recommendation, I have replaced the original USB ports listed in this thread with a Blue Sea 1039 4.8A model. Some minor tailoring of the switch opening was necessary but I've been very pleased because the Blue Sea port provides all the power needed.

Here’s the Blue Sea installed. Wiring is the same as described in my original post below.



Original Post
Others have done this but for what it's worth, here's my experience with adding USB power ports in my 4th gen 4Runner. It's a very easy mod that didn't take 2 hours total despite the problems with the plug, painting, etc.

I first used this product, which definitely presented some challenges as described in my Amazon review.

But all's well that ends well so here is the story. Fortunately, it's very easy to install and access the port so that made the problems much more tolerable.

1. I used quick splices to tap into the 12V power port outlet in the console. Considered using an add-a-circuit but this worked fine. Like the power port, the USB port is controlled by the ignition. Things to keep in mind - as others have noted, be sure the wire you're placing into the quick splice is all the way in and squeeze the metal part all the way down, and be aware that the quick splice things have this conductive jelly stuff in them (much like Vaseline) so have a rag or paper towel handy to wipe your hands before handling any other parts. (Edit: use Scotchloks if you can, they work much better.)

New edit: This pic was taken with everything plugged back in and ready to reassemble. Before you start the wiring part, just unplug the white power port plug and blue DAC switch plug. Each has a locking tab on one side and may be tight, so squeeze the tabs and gently work them until they come out. Then lay the big console piece aside and you'll have the space you need to work.



2. Here's how the port looks if installed as sold. It fits the opening perfectly but isn't anywhere close to a match for the OEM switches. BTW, I saw a question about how the OEM plugs come out of the openings in another thread. It's simple, they're held in by tabs and easy to remove.



3. The blue light won't even be noticed by some owners but will probably seem like a blinding blue death laser to others. I fell in the middle. It's not awful but it's at the bottom right limit of my peripheral vision so it was kind of irritating at night. Pics don't do it justice...it's not that passive for lack of a better word, it's pretty bright. See solution below.



4. Since I didn't like the shiny finish, I decided to take the port out and paint the easily removeable cover to better match the OEM switches. Two light coats of flat black and one light coat of a clear matte protective finish (figured it would help the paint hold up better in the long run) did the trick. Wasn't worried about covering the USB logos and figured it might help with the blue light too.



5. Painted and reinstalled.



6. It did help with the light. I've also ordered black dust plugs which will block it completely and keep gunk from getting down into the ports. I'll post an updated pic once those come in.



If anyone has any questions, fire away.