Depending on how serious you are, I'd pitch the designs to both Rooster Teeth and Volante Designs and see if they'd be willing to work together. My personal favorites are Crescent Rose and Gambol Shroud.
Man you should totally do a indiegogo page of your hoodie designs. So that you may raise funds for how much it would take to get them made. Plus I'm sure everyone would support having this hoodies made real.
Haven't legit pitched it as of yet haha I remember on the podcast they mentioned how they made merch that people voted for yet no one bought it... This kinda makes me skeptical of pitching it actually getting made lol
Start a poll on your page with the estimated price of the hoodie and see how many would buy it for that price. A lot of the time people will say they want or that they'll buy it, but when they see how much it really is it scares them off. And if you get enough support you have even more support for your pitch. B)