I don't see how that's different from contacting a manufacturer and having them produce your product.

If you want the first-hand experience, it's usually up to you. Shared tool access is becoming more popular with the (hac|ma)kerspace scene, but even they have a hard time acquiring professional/industrial machinery of that scale. The insurance/risk in allowing you to operate it is not insignificant, either.

Best thing to do is to continue promoting personal-scale projects (like the one linked) that are developed to be accessible, but don't necessarily meet criteria to be production machines.

On sites like etsy you can find people with the older hand crank circular knitting machines to make socks for you. There are loom and shuttle clubs in most areas that would be a good place to ask. There are a few companies in the US like Chrissy's knee high socks that have industrial machines and take custom orders.

Freakers[0], a company featured in a documentary on crowd funding, rent time on sock machines, to produce bottle cosies/beverage insulators. Maybe you could contact them for details?

[0] http://www.freakerusa.com/