Krystal,
Honestly I think it would be a little short for them. The picture I saw which I copied this box from was the same size (4' X 4') but was only divided one way. I should have made it like that, but as I was cutting and welding I thought the compartments looked larger. It will still hold a good size dog in each box, but it won't be the most comfortable trip they've ever taken.
Circle C / Brute,
If I could count my time I definately have more than $150 in it but its not worth anything sitting out by the barn killing the grass. I would rather someone be getting some use, and the rest I'll chalk up to welding practice. I enjoy tinkering with stuff anyways!