I would definitely check out the airline you are going to fly.  The measurements for carry-ons change for 1 to the next.  Also, the weight limits and charges change.
I fly to Alaska to hunt on a regular basis.  If you can fly Alaska Air I would advise it!  I carry on my Kifaru EMR2 (which is huge loaded) and it fits in the overhead baggage of their planes.  I compress the EMR2 so it's close to the max measurements.  Alaska Air also allows an extra carry on "bag".  I carry on my EMR2 plus a giant camera case loaded with my spotter, cameras, camcorder, etc.  It's a royal pain in the rear but I usually carry on around 70 lbs of gear this way.  I get a lot of looks in the airport!
Another thing I've learned is to gut the foam in my giant rifle case that is on rollers.  I fill the rifle case with clothes, fishing rods, trekking poles, etc. until it reaches the maximum wt.  It's nice having a rifle case on rollers so I can place other baggage on top of it for hauling through the airport.