Since you asked for opinions, I'll weigh in:
They are "only" sideboards. It isn't like it is main bearings or transmission gears. I wouldn't over-engineer a solution since it isn't a huge commitment if you don't like what you end up with.
I think it all comes down to your color scheme. The sideboards I've seen are painted white to complement the truck's secondary color, and look fantastic. Grain is fine, but I prefer it on furniture, not sideboards.
When I got my truck, it had varnished oak bed boards. I'm going to refinish them in (original) black. If I were re-bedding the truck, I'd probably go back to the black coated SYP. Mar-K's research, if I recall correctly, showed the black coating treatment to last the longest. Stands to reason, being that it probably is the most UV resistant.
Of course, it comes down to YOUR personal preference. Factors that may come into play are color scheme (including whether you have black walls, narrow whites, or wide whites,) current bed treatment, your truck's storage situation, your pocketbook, and how deep your commitment is.
Good luck, and please post a photo once you finish it. I'd like to see it!
Bill
