There is another option, but it definitely has an element of risk to it, since you'd have to trust your customers. You could sell very high quality versions of your designs (in a printing happy filetype) to people digitally and let them print their own things with them, with a promise of keeping the designs private. Paypal for collecting money.
I did this for a design I did a few years ago. Since it wasn't a business thing for me at all, it didn't present a stressful situation for me, like it likely would for you...I just thought I'd throw it out there.
Here's a sweatshirt I made with mine: