my dad recently made his own bike rack. different car, but it should fit any car with a trailer hitch. the trailer hitch was custom made as wel. and slightly moddified to support the rack. it's not really on the light side but it works rather well.
depending on what you want and useing parts from an existing roof or hitch rack it's not to hard to make something that suits your needs and fits your car, if you have the tools and the time..
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