Consider pairing the rolling laptop bag with a carry-on sized soft bag. I use a
TLS Weekender on top of my rolling laptop bag. The TLS has a pocket with a harness for a laptop and, because it doesn't have the frame and hardware of a roller, it holds more stuff and fits into smaller places, including under seats. I use a
Bag Bungee to attach my bags together to roll through the airport. As an added bonus, I can take both my roller and backpack onto regional jets, so I never have to gate check. Your Samsonite might be a touch to big for that.