Hope you don't mind, but with slight modifications, I'm going to steal your design. I have an outdoor wood boiler about 60' from the house, and up to this point, I've just been tarping my wood during the wet and snowy months. I've been running ideas through my head for a more permanent solution for a few years now, but after seeing your design, I'm thinking it would be nearly perfect for my needs.
Do you have any support down the center of your span? I'll be stacking heavy hardwood, and I think a 4' span might be a bit much for the weight I'll be putting on it. I also won't be splitting my pieces quite as small as yours, since my boiler will take pieces pretty much as big as (Ok....bigger) than I could possibly lift.
Your work looks great, and thanks for the idea.