If you can't find one, you might like the Katabatic Gear Palisade 30F quilt ($315). It uses almost the same amount of down (9.2oz) as the Ultra 20 did (9.5oz), yet it's lighter (17oz vs. 19oz). It might actually be warmer too since they claim to use 850fp down vs. 800 fp down (not that I trust the specs above 800 much).
I've got an Ultra 20 in nice shape and I love selling/buying gear, but the Ultra 20 has been awesome and I can't think of a good reason to sell it, since I would have to replace it with something that costs way more (ie. the Palisade).