The trail on my Napoleon's field carriage is laminated, as is the bed base for the ¼-scale Coehorn mortar.
In the case of the field carriage, this was done more for convenience than strength. It's a lot easier to find good wood in standard sizes, and I was able to laminate to the width I needed by mixing thicknesses. But it did make a very solid and strong beam. I seriously doubt the trail, laminated from five oak boards (¾"-¼"-¾"-¼"-¾"), will ever warp.
In the case of the mortar bed, laminating allowed me to use oak that I already had on hand.