I have gone the other way.
I use a standard carry on wheelie bag and in it I fit a Frog Indigo wing with aluminium back plate, shorty, boots, Apeks Regs with single SPG (miflex hoses), mask, a shorter copy version of the Scubapro Jet fin, travel towel and swim shorts and my netbook. It comes to about 14/15 kg
Then I have a light weight duffel with a couple of changes of clothes wraped around my strobes - it looks big but it is light weight.
So when I check in I throw the big light weight duffel on the scales and it is well under weight. And so far they have never tried to weigh my carry on bag. My digital SLR I usually leave with a friend when I am checking in or whear on a strap around my neck with my jacket over the top (might be a bit hard for anyone with a big belly but works for me)
The rest of the time I just carry it around in my hand. On the plane I just wrap my jacket around it and stick it in the over head (after I have weight lifted my carry on wheelie into the overhead)
If they loose my luggage - Im still going diving.
I have heard to many horror stories of people turning up for liveaboards with all their dive gear lost in transit. I can always buy a couple of pairs of shorts, T-shirts and a tooth brush but I cant replace my dive gear.