I am not brave enough to undertake a snowboarding jacket - especially since I can get one pretty cheap at Old Navy.

But, since you're obviously a much better sewer than I, I'm sure it will be fine. They do have that mesh venting in the armpits. I don't think there's usually anything fancy as far as venting in pockets in the front. Those pockets are usually just normal lined ones that are used for keeping money, Ipods, keys etc. safe.

You may want to buy a jacket and see how they did it and then just take it back...Also, just in the experience of my two teenage boys who do a lot of snowboarding - they have never opened up those zippers...They look cool, but if it's that warm out, they don't wear their jacket, they just wear a hooded sweatshirt! So, maybe you don't even need those zippers!