I'm planning on buying this Salomon Jacket with a rear pocket (and plenty of front pockets) for this sort of thing: http://www.salomon.com/us/product/el...-jacket-m.html (and just carry water in a light, single bottle carrier).

I used to hate hydration packs also, but the new ones move quite nicely with the body (e.g., Salomon "Agile") and it's nice having the luxury of all the space.

Also, Ultimate Direction has a 2-bottle pack that's meant for skiing in the sense that it's very compact and the bottle don't get in the way of your arms swing. "Chest" in center is decent sized with a compression strap.