So the REI and most other bivy's are not meant to be used alone, without a tarp? What's the point then? It eliminates ease of use and a lot of the weight saved. And if this is the case, can you point out a completely waterproof bivy?

The extra clothes I bring don't add up to more than a bag that most people could afford. Sure, you can get a bag that's lighter. For $350 and up usually. In the mean time, I'll bring an extra $50 fleece thank you!

What I intend to achieve with the tripod and poncho is actually the opposite of counter-productive. Think about it. The poncho, draped over and secured to a tripod, gives me a whole lot of room to breath into. Rather than breathing into the bivy, I'm breathing into a big open space. This is obviously only for when the weather forces me to do so.