sounds alittle bootleg, but i always just tied mine to the bumper in between the grille and bumper. I have one of those large chrome bumpers. I live in ohio so this works for me and nobody second glances it
. just be sure to wrap the middle edges of the board to keep it from jiggling around on the freeway and/or damaging your board/skis/grille. strap it down really tight. you can actually fit 2 boards easily putting them together snow side/snow side.
The reason i do this is that im too cheap to afford a hard top or the exterior bar frame cargo thingie. works for me.
also i hear there is a mount that tightens to the spare tire and can hold two boards. or a (thule?) rack that connects to the hitch and carries, like, 6 boards horizontally behind the spare like some types of bike racks.