Those Klymit things seem to have this undercut a bit @ 250gish. But thats mostly because they've cut some rather large holes in them, which going by reviews isn't a universal benefit :)
The new, lighter neo airs are only 350g but a lot more money. Also, to be fair, warmth.
Suppose their answer cf warmth would be to get a thin CCF pad (they do some very light ones) and add that. Works out cost wise, weight wise almost reasonable. Bulky perhaps.
