I would love to do it if I wasn't so busy with other projects! ....but a big factor is also cost. Despite being able to build a mold for next to nothing, I couldn't hit the prices that they charge for these things. That's why they build them in China lol. If I have 5,000 of them made for me, YOU guys would understand quality and purchase them, but the people on Ebay and Amazon just see a hide box and a pricetag so when RBI charges $7 for a large hide box, they would blow me out of the water as far as price goes and win that battle every time.
Another dirty little secret is that they are probably using the same mold for several different companies (which China can do because they don't follow patent restrictions or intellectual property rights)....try that in the states and you would be sued into oblivion.