You've probably found one by now, if not I would try Jumbo Loisirs (Meyrin), or maybe Décathlon Meyrin (next to Media Mark).

The biggest car accessory supplier that I know in Geneva is Technomag in Vernier, Chemin Delay 42. I enclose their website link : http://www.technomag.ch/fr/partner/vernier.html

The shop is just unusual in the sense that it primarirly servces trades so you ask for info at the desk and they go and get the parts/accessory you need. Very helpful though each time I visit. Best to go with a photo of the rack you want.

Cheers

Sam

Woodhouse Carpentry
Custom furniture making - fitted cabinets & bookcases - interior & exterior woodwork

Telephone 079 763 58 97

Workshop address: Route du Nant D'Avril 51, 1214 Vernier
Postal & Office address: Rue de Saint Jean 23, 1203 Genève

Examples of our work on our website: www.wood-house.ch

Client feedback on our Glocals business listing: http://www.glocals.com/guides/biz/Woodhouse-Carpentry/

Follow us on Facebook : https://www.facebook.com/WoodhouseCarpentry

Read the recent article about us in Know-It-All : http://www.knowitall.ch/local-news/your-home/make-yourself-at-home/1992-bespoke-furniture-and-custom-designed-woodwork-projects-from-woodhouse-carpentry

Thanks to both of you! Ended up going over the border but glad to know it is not necessary for next time!