As if it weren't hard enough to get a date in this town, ecosexuals add another kind of green to their ideal mate's personal profile. ______________________________________ San Francisco designer Rachel Pearson, 33, owns a successful line of children’s clothing made of organic cotton that also meets international fair-trade rules. For herself she favors clothing from thrift stores—“Not buying new,” she says, “eases the toll on the earth.” A vegetarian, she recycles religiously and loves to pamper herself with yoga and meditation. There’s another arena in which Pearson upholds green values, and it can create a bit of an etiquette problem....