This could be the iPod touch 5. Photos of the prototype body show a different design and an old connector.
The first Apple iPod with a Lightning port was the iPod touch 5. However, photos of a prototype of this device have appeared on the web today, showing that Apple originally intended to endow this device with the old 30-pin connector. More precisely, the source received at its disposal the body of the prototype, and not the entire device.
What prompted Apple to change its decision then, we are unlikely to know, but in the end, iPod touch switched to Lightning back in 2012, along with the iPhone 5.
You can also see that the prototype even looked almost like an iPhone 5, with a case with smooth edges. But in the end, the production model became thinner and rounder. iPod touch 5 stayed on the market until 2015, after which it was replaced by a new generation model.