Check this out

http://luckynino.blogspot.com/2009/03/eclipse-mtb-supertube-56g.html

I wonder how strong it really is.  If it ever comes to market then it would be worth a try.

Alex G:

...as long as the sealant level is good (I think you have to add some about once a month), you only need to carry a C02 cartridge instead of a pump in the event air is lost from a sidewall puncture (i.e. find the puncture, shake the tire, inflate). One less thing to mount on my frame and I don't have to worry about carrying or installing a new tube on the ride.

I only add sealant every 4-6 months. I live in western NY where it's not particularly hot. You don't have to add two ounces, either - just one ounce will do.

Only vulnerability I can see with the Eclipse tubes is a susceptibility to pinching, either during mounting or riding. Sort of like latex tubes in that regard. "The material of the tube is so resistant it is almost impossible to get a snakebite. " Super elastic but super tough. Hard to believe. And you still have to use sealant.

Jasann:

Can you put them on a 50mm carbon wheel? From what I see, they only come with small valves.

 Sure you can.  I ride Corima Aero tubeless.  45mm deep rim.  They came with Corima's tubeless valves, which are long enough, and with valve extenders.