Following up on what I found. I wanted to avoid the add-a-fuse taps because they can stretch out the connector or don't sit flush, so this is what I did.
I was able to get a fuse block out of a junkyard van. The 16344, 16345 or 16346 do appear to be the correct connectors compared to what came from the factory (thanks, Greg!). Not sure if the fuse blocks are all the same, but if you have some unpopulated fuse holes, it's easy to add a new 12V circuit inside the van.
Look for your unpopulated fuse and check to make sure the other leg, has the right behavior you want (12v keyed on, 12 always on, etc). Then wire up your new circuit that you want power to with one of your connectors.
You can pull the fuse block from the mount under the dash by undoing the clip on the right side. Push it away from you and it will come out of the clip, then you can rotate it.
Pull the red cover off so you can insert the new connector into the unpopulated spot. The cover pulls off from the front. Wiggle it and it will pop off. Align the connector with the little fins into the slot. Push it in and you will hear a click.
If you need to pull it out again for some reason just lift the little tab with a small screw driver. Then pull on the wire from the back side.
Put the red cover back on and push the fuse block back into the mount. Connect whatever load you want (wire-size/fuse limiting of course) to the other end of your wire. Then insert a new fuse into the block to provide the circuit with power.
I'm powering my locker and dash 4x4 switch this way. I harvested one of the connectors out of the block instead of ordering one from clipsandfasteners.com.