See: Serfas Thunderbolt. Alternatively, Knog Blinder 4V.

Here's a question - how do they charge that? Do you have to remove the seat from the bike? Do you have to have power near the bike and plug it in?

Question 2 - I don't see how one stated feature - lighting even if you have a saddle bag - is any different with this than with a Thunderbolt or Knog. You can slide either of those anywhere along the length of the seat tube.

In order to make my light visible with just a wedge bag, I had to make an extender. If I had an actual saddle bag, or a rack trunk, the entire seat post would be obscured.

This is the only way I got significant visibility from a seat post light even with a wedge pack:
http://www.thingiverse.com/thing:65732

As you can see in that photo, if I had a light like in the Kickstarter, only maybe less than 2 inches of it would be visible, the rest of the light (and battery power) totally wasted behind the bag.