I found a good switched power source in the fuse panel behind the glove box (see
this thread for instructions on releasing the glove box to access the fuse panel) to run your radar detectors, GPS devices, or other hard-wired accessories. After doing a lot of research and knowing that I only needed 2A to power my detector, I narrowed the possible candidates to the following 5A circuit:
Fuse Location 07 - Park Distance Control / HomeLink (Garage Door Opener)
This fuse is the 2nd 5A slot in the 2nd row from the top. Note that your X1, depending on year, trim, options, and maybe regional market, may have a different fuse panel layout. However, you will likely still have a HomeLink fuse slot somewhere (even if it's not in slot number 07).
I then used an Add-A-Circuit to tap into this existing power source. If your new device doesn't power up on the first try, you may need to flip your Add-A-Circuit fuse adapter 180-degrees (reverse slots).
Why did I hard-wire my Valentine 1 radar detector to the fuse panel when I could have used the "Blendmount" and "Mirror Tap" products to obtain a switched power source near the rear view mirror? Short answer: More physical space and clearance for the V1 direct-wire kit and accessories. I needed some place to hide the Valentine 1 (V1) Brown-Out Booster (BOB), which maintains power to the V1 during Auto Start/Stop cycles so the detector doesn't turn off and reboot (making lots of beeps) every time the X1 automatically shuts its engine off at a stop. The Brown-Out Booster is the same size and form factor as V1's direct-wire power adapter, and there are limited options for hiding either of these up near the mirror using a Blendmount and Mirror Tap. I also considered the Valentine 1 Savvy product that gets power from the OBDII port, but it's expensive (compared with the YaV1 Android app that has more features) and I didn't want to leave something plugged into the OBD port all the time in case I want to use it for something else one day.
For anyone wondering, I didn't have to remove any interior trim panels to hide the V1 wires going to the V1 (mounted high by the rear view mirror) or concealed display (near instrument cluster). I was able to hide the wire in the headliner, behind the rubber weather stripping down the A-pillar, and other interior trim down in the footwell.
I hope this thread helps others looking for a good switched power source in the fuse panel.