I have a V1 wired into the mirror on my Corvette, I was able to purchase a mirror mount and a 8" power cord that had pins crimped on the end that pin into the mirror power connector. It is called an "Invisicord". Their website shows that it has been adapted to the Odyssey. Click on the "installation info" and enter the vehicle, it tells you what wires in the mirror connector to piggyback the pins.
I wouldn't recommend it. In my other car, I hard wired a Whistler XTR690 radar detector to my autodimming mirror and at first everything seems fine. The radar would turn on when I started the car and powered off when I turned off the ignition. Everything seem to be working as I was getting the warnings and flashes. Then I started noticing the radar started loosing its user programmed settings. I thought my unit was bad and sent it to Whistler for repair. I actually had a Whistler repair technician contacted me to discuss my radar. He said he ran a battery of tests and found no issues. He asked where I was getting power and I told him from the rearview mirror. He tells me its difficult to tell how much current the thin wire on the rearview mirror can supply. When I got it back, I hard wired it to the fuse box and no more problem.
There are 2 questions you need to answer before wiring to the rearview mirror. 1) How much current (not voltage) will your radar detector require? 2) How much current (not voltage) the factory wiring on the rearview mirror can supply? Without using a multimeter to test amperage on both sides, you will not know. Also the biggest problem is what I ran into which is the radar powered up but the circuits inside wasn't getting enough juice to operate optimally meaning the radar antenna probably wasn't working as per spec as it should. The radar probably wasn't detecting the radar traps as well as it should.
I know my story applied to a different vehicle than the Ody but until you can truly answer the above question 1) and 2), you will not know if your radar is getting adequate current source to operate properly.
Radar detectors these days draw so little power that I am more than sure the wires used to power a rear-view mirror are more than adequate to provide the required juice.
Another problem that one might have is poor contact, that can certainly inhibit flow of electricity.
I am ordering a new Escort today, will test its actuall draw from its power supply and will post my comments post-install on my findings. If I measure the amp draw to be higher than expected I may use the direct wire methods found online.
Thinking of ordering the Invisicord option for my ESCORT SOLO2 with my 2012 Odyssey (likely to upgrade to the 9500 soon), curious how long I should get the cable... any folks have thoughts who've done it? I would likely be placing my mount to the right of the rear view mirror, or possibly underneath the mirror. I don't want a bunch of excess cable but I also don't want it to be too short.