I realy like the cork helmet idea, But there is no way that thing has anywhere near the ventilation of a good road helmet or even mtb. That comparison has to be with multi sport helmets. as far as protection I don't see way cork couldn't be made as safe as foam but I would also be skeptical....
Did you try outlier, and swrve as far as clothing goes. Pricey but I'm gonna guess cordarounds arn't cheap either. If it's made in the u.s. your gonna pay.