The iPod touch 6th generation can be jailbroken out of the box, because it comes with iOS 8.4, and the PP iOS 8.4 jailbreak tool for Mac works with the new iPods.
In fact, I just jailbroke my device no less than 5 minutes ago, and it worked without a hitch. If you guys have kept up with me, you know how much I absolutely loathed using my 5th-gen touch due to its pedestrian speed.
Seeing that the new iPod touch packs much more power than the device it replaces, I'd say this is a good candidate for a jailbroken device, or at the very least, it might become my go-to test device.