I was looking into this topic recently also, and found a TB member who had some experience with Rustoleum Restore - a thick textured coating for weathered wood decks. It seemed like an interesting option since its available in a pretty good range of colors at Home Depot, and a 1-gallon bucket runs about $40.
I happened to find a gallon of it in battleship grey on the "oops" shelf at my local store a few weeks ago, and couldn't say no to the $9 price tag
I haven't messed around with it yet, but I think the biggest challenge will be to keep it from forming the nasty craters that the samples in the store's display exhibited. Restore also seems to contain some gritty substance that leaves it with an abrasive surface, don't know if that can be tamed. Will report back after I've tried it out.
I happened to find a gallon of it in battleship grey on the "oops" shelf at my local store a few weeks ago, and couldn't say no to the $9 price tag