Richard,
We have a couple of Cedar's available. None of which is vertical grain or kiln dried. I am using more of the Rough Cedar but it's used only for less detailed work.
I seldom, if ever, recommend YP to other sign artists because most don't have a CNC. That's the deal breaker. Even on this forum there aren't many folks familiar with gluing up sign panels. We started up years ago when that was the way it was done.
About longevity: With a well prepared YP panel, I can't see why it wouldn't last. One little note, I've been treating this material with Borax to eleminate bugs or wood eating pests.
To my knowledge, I'm the only sign guy using this material on a regular basis. It's been a couple of years and all looks good so far.
My HDU use is to close to nothing and my Redwood is 0. All of which reflects considerable increase in profit.