I made something like that for bringing my bike on the train when I lived in Europe. I haven't used it in the US though. I made it out of a couple of super-cheap fleece blankets, a long zipper, some velcro, some buckles, and a couple of long pieces of webbing. The bike went in upside down with the handlebars turned and the wheels off, and the wheels went in big pockets on either side. It took only a few minutes to pack and unpack and was light and compact enough to carry in my saddlebag on a ride. It was easy to carry and worked well.
I wouldn't try checking the bike as airline luggage that way, though. And I haven't tried it on Amtrak in the US - they seem to be much more uptight about not letting people clog up the trains with gigantic suitcases, even though their checked luggage system (where it exists at all) really sucks. It would probably work well on a bus, provided that you can pay attention to how stuff gets packed in with it, and it would probably work on public transit or commuter trains.
I've been looking for something like this for a while now because it will save me so much money in fees and stop delays when I get the 'no bike carriage' problem. Most European trains and the Channel Tunnel allow oversized luggage on for free. Many have specific regulation stating that a bagged bike with the wheels off is ok.
Housse is a French word for cover. The French railroads used to require a cardboard housse for bikes on many trains. Unlike the bag in the photo (which I have used on TGV trains in France for my folding bike), the cardboard housse was open on the bottom and only covered the drive train. You could still roll the bike on its wheels, I think. Air France also used them over 10 years ago. I have no idea if they still do. BTW, these days, most French non-TGV trains have hooks to hang bikes, which makes it very easy to bring a bike on board.
Nearly 100 percents of Russian cyclotravellers use something like this for years, the idea is definetly good. Funny, but it was impossible to find something like this in Germany, everything is too bulky, expensive and not really suitable for touring. Typical weight is about 1 kilo, they last easily for 10-20 trips and you can use it as a rain cover and even a bivvy
It says PIK 99 (manufacturer), TransBaikal trip 2001, by local cycling club Velopiter (St. Petersburg). Note, these pictures are not mine but from the Pik99 page.
There are at least two companies making such, both based in St. Petersburg: Pik99 and Equip.ru (links lead to their bike bags).
There is one killer feature, use it as a Spinnaker sail when the terrain allows