Hmmm, of the choices you outlined, and based upon what is readily available, I would choose Epic-treated ripstop nylon. Outdoor Wilderness Fabrics supposedly has some right now, although it hasn't hit the catalog yet. Their current stock is reportedly sub-2oz.
Be aware that Epic has issues with poor breathability in temps below freezing, but is otherwise a good waterproof breathable performer. But by contrast, Goretex always has issues with poor breathability, Momentum isn't waterproof enough, and silnylon is not breathable at all. Event would be your best choice, but it isn't commercially available, so you'd have to convince a gear manufacturer to sell you some of their stock.
Yup, I think Epic is the ticket.