I have a camera bag and laptop backpack I travel with. That counts as 2 carry on. The only reason I have two is because they are purposefully built. Mind you, I have modified the camera bag a bit to accommodate the housing and strobes.
What I'd like to do is modify a normal roller board carry on to be both a camera and laptop bag. I'm starting to play around with a couple of approaches using rigid black foam for the camera section. I am taking this approach because my wife and I only travel once a year for diving so I'm not really motivated to purchase a specialized bag.
One aspect I'm keenly aware of is that any carry on needs to be prepared to be checked. There will be sufficient packing to allow this.
Normally, when I come with an idea, someone else has already tackled this so looking for any tips from those who went before me so to speak ;-)
Thanks