I beleive he is referring to true 2" x xxx" rather than milled to 1.5" x xxx"
I've got a pile of freshly oiled (shingle oil) 2x8's sitting on the garage floor waiting to go back into my trailer, all I need to do is hurry and clean up the trailer a bit and rattle can it (its pained I just want to give it an additional coat). I looked at doing some synthetic stuff, but cost, weight (they are heavy) and strength (they sag across long spans, even without much load. Another option we tried to track down was laminated scaffold plank material, super strong, super durable... and super expensive... redwood it is.
Yeah, you take good care of that trailer. BTW, that silver is Hammerite in case you were wondering.