Thermarest has taken up the challenge of Big Agnes 270 gram AXL Air Pad and presented their new offering a 250 gram Uberlite pad at the Outdoor retailer Summer show in Denver. Of course it is also an uninsulated pad and so comes with a R-rating of 2.0 which would be fine for most summer nights. I imagine it too will find a following amongst the ultralight crowd who only go camping in the warmest weather. It seems that it is mostly a Noeair Xlite in a slightly lighter material and with the internal reflective barrier deleted to save weight. It is likely to retail for approx US$180. Available in 2019. Clearly you could cut this down to 230 grams at 5′ 6″ or 208 at 5′. Next year they will have a pad so light it carries you.
PS: Mind you a few years ago AMK were selling a pad which only weighed 186 grams: http://www.theultralighthiker.com/some-interesting-stuff-here/
PPS: See also Thermarest’s new quilt/s the Vesper at 15 or 19 oz: http://www.theultralighthiker.com/thermarest-vesper-quilt/
PPPS: I will probably be sticking to my trusty Thermarest Neoair Womens at 340 grams and R= 3.9 for most trips: https://www.theultralighthiker.com/2018/08/15/womens-are-great-in-bed/ It is comfortable down to below zero Celsius.