Thanks for the suggestion, but couldn't locate such a thing. I ended up going to a local stereo installation shop, and with their assistance we ended up using the spare (sealed off, nub looking) cable pass throughs on the factory grommets on each side of the vehicle. According to the shop, you can easily pass up to 4 gauge wire through each one of those additional pass throughs. So, power (10 gauge) and one antenna go through the grommet on the passenger side, and one antenna is going through the grommet located on the driver side. Took them about an hour to do the install, labor was very reasonable.