After some research, I'm approaching the weight of my CCF pad with a more comfortable half-inflatable pad:
I've bought a cheap (it was about $18, now I found one for $10), plastic inflatable pad from china (http://www.aliexpress.com/item/Ultra-light-318g-UL-outdoor-inflatable-cushion-sleeping-bag-pad-outdoor-beach-camping-mat-moisture-proof/1800816029.html). It doesn't look very nice but it feels more durable than it looks. The weight, 330 g, is sligtly more than what the sellers claim but still on par with the other lightest full-length inflatables. It has two chambers, so I cut one to have a torso-length pad (actually, it's longer, and my head fits on it as well). I sealed the other half so I got two of these for that price.
Then, I added a piece of a reflective insulation from a hardware store under the legs. It's thin but it provides some insulation, I can put my pack under my legs if necessary. Making the pad full-length saves me the hassle with mating two-part system. With such a pad, I can skip the groundsheet if the conditions are good. The pieces are joined with Tyvek tape, it holds well on the plastic.
I also reinforced the area around the valve with a piece of fabrics backed Tenacious tape as it looked like the weakest point of the pad and the tape might provide some protection.
The result is a pad that weights 199 grams and is surprisingly comfortable. What I really like is that the inflatable part is 60 cm (23.5 in) wide so there is more room for my hands than on common inflatable pads. The inflatable part ins not very high so the drop is not a problem for me. I've tested it on an overnighter and it worked great – now we'll see how long it lasts.
Edit: Weight of the original pad added.
