Personally, I used yakima Q-towers with a 48" crossbar with wheel forks and the yakima copperhead. I prefer roof mounts and i've found them much more reliable then a trunk or reciever mount. All together it'd probably run about the same as getting a receiver made and getting a rack.

I've always found it easier and more reliable to mount from the top then from behind.

My Hybrid

2004 Civic w/ CVT
Magnesium Metallic
my commute 53 miles each way