I've seen the sandblasting done on the bed before. I think they did it on Chop Cut Rebuild on a '53 Chevy. Really brings out the wood grain. If you're going with Helmsman, you're going to have to put a dozen coats on before you have a smoothe layer.
As far as staining pine wood to the color of your desire, if you're not building a show truck (and if you're considering using POR15 on the bed, I'm guessing you're not) I'd say go for it. I just finished staining pine planks with Brown Mahogany and covered it with 3 coats of Helmsman. There are spots with lighter layers of stain, but I think it came out great. I have one more coat to put on the bottom of the boards and then I'll be installing them tonight or tomorrow. I'll post pictures on my webshots when it's all done.
