Sorry to interrupt your otherwise fine take with actual data, but here's the facts.

Because the final piece was destined for a landing page we rendered at 720, layered EXRs at more like 13mb per frame. We only needed 24 fps.

The IO was no big deal, since we were copying the frames down as they rendered. Our download speed was fast enough to keep up with the ec2 farm.

The theory behind your point is sound, and is the main reason we didn't go with a 3rd party service. We've certainly been burned when the download took 3 times longer than the render. But amazon has great throughput and the whole thing was really smooth.

In case you want to see the finished animation, it's here:

http://www.intel.com/content/www/us/en/home-users/unfold-whats-possible.html

That's what we used for this project. Luxology gives you 50 render nodes for each license of modo, and we had 6 licenses, which allowed us to legally render on 300 machines. I don't think any company comes close to Luxology when it comes to licensing. They license to people, not nodes. And you can't beat the modeling and rendering tools. We animated in Maya, but refused to use Mental Ray for rendering. Renderman is great, but the per-node price is a killer. The star of this story is ec2, but without modo it doesn't work at all.

Have you seen our work? Prepare to be "glad." http://www.intel.com/content/www/us/en/home-users/unfold-whats-possible.html I'm rather proud of it. Those four vignettes were rendered in one week, which is the point of TFA, but it was months of blood sweat and tears. The cloud just made the deadline possible.

We used spot instances for most of the project, averaging a bit more than 50 cents per hour. Spots are great for rendering because we didn't mind getting outbid - we'd just do that frame again. The hard part was writing the script that tied it all together.

> The article linked above refers to "Halfnium" I think that's a typo. The actual substance is called "Unobtanium" and was originally used to drill down to the center of the Earth.