Below is an interesting excerpt:

"Logistics

Several decisions were made early on in the production of this movie that I can only speculate on. For one, we choose to animate and render at 24 frames per second (fps) even though that’s not broadcast video. However, 24 fps does divide evenly for animation, and it is the traditional film rate. Animation:Master easily converted the few animations delivered at 30 fps or 25 fps. Also, our chosen resolution of 720 X 405 is based on HD 720p with a 16:9 resolution. TWO is 90 minutes long, almost 130,000 frames with an average render time of 25 minutes per frame, which equates to over 60 thousand render hours! Over 100 people participated in TWO’s making."

You should send them a quick revision of that bit. "720p" refers to the vertical dimension of HDTV. 720 scanlines. It doesn't make any sense to say that our horizontal dimension came from that figure. An actual 720p frame would be 1280x720.

I always wondered about 720x405. I just figured it was to save on render time.

Actually, I don't know where that resolution came from...

Soooo.....has this resolution been tested on a tv?

It looks great in NTSC.