The Dorminator (latin anyone?). Bonus points: no mention of the overused 'lite' suffix.
Adding to the comment about the usefulness of 'X' in a name with my 1st idea, how about the 'Dorminatrix'? No foreseeable problems with that, right?
Or, if you would like to advertise the warmth aspects, "Thermonator" or "Therminator"
As the holder of a marketing degree, I should be able to do better :(
More seriously though, using or combining geographical features or names of geographical regions and adjectives for warmth, rest, and lightness seem to be quite popular and the default solution to naming something. Rational differentiation in mainstream outdoor gear can be difficult these days, so emotional appeals are quite important to TNF or Columbia making another 3 in 1 jacket. It matters to niche mfgs too. Golite has the fortune of their brand name evoking a predetermined feeling about their gear no matter how accurate it is, so they throw a bunch of hyperbolic nouns and adjectives in their product names that don't need to involve lightness. Adrenaline, Ultra, Utopia, Quest, Jam, Rush, Shangri-La, all distinctively targeted towards the purchaser's perceived activities with each item. I'm actually quite impressed by it. Those are their hard goods. All their clothes have either specific (but obscure) or general landform or location names.
Never go too mainstream with your geographical entities though, for risk of sounding pedestrian to consumers who wish to feel very far in the loop. (I.E. Mountain Pad, or Everest anything unless you would truly use it on Everest). The 'list of landforms' on wikipedia could also be considered a partial list of outdoor manufacturers and products.
Combing all these words into a rondomizing generator would produce lovely names like the "Dainty Valley Pad" or "Sleepy Spring Pad", aggressive names like the "Lava Lake Mat", or plain undesirable names like the "Dirt Cone Slumber Pad". I'm sure our creative members could have some fun with this.