I have about 10 different scented soaps on my drying rack right now and haven't noticed that the scents have transferred at all.
I use stacked plastic shoe racks for my drying rack. I got them for about $3 each and have about 7 of them stacked, to make a 7 ft. rack. I try to keep each scent on it's own level, and if I have to put two on one level I will put two that are similar.
I also cover this rack with a thin plastic drop sheet to keep the dust (and cat hair 8) ) off my soap. I just drape it over lightly so the soap can still air out.
Works for me!